logicaffeine_compile/

compile.rs

//! LOGOS Compilation Pipeline
//!
//! This module provides the end-to-end compilation pipeline that transforms
//! LOGOS source code into executable Rust programs.
//!
//! # Pipeline Overview
//!
//! ```text
//! LOGOS Source (.md)
//!       │
//!       ▼
//! ┌───────────────────┐
//! │  1. Lexer         │ Tokenize source
//! └─────────┬─────────┘
//!           ▼
//! ┌───────────────────┐
//! │  2. Discovery     │ Type & policy definitions
//! └─────────┬─────────┘
//!           ▼
//! ┌───────────────────┐
//! │  3. Parser        │ Build AST
//! └─────────┬─────────┘
//!           ▼
//! ┌───────────────────┐
//! │  4. Analysis      │ Escape, ownership, verification
//! └─────────┬─────────┘
//!           ▼
//! ┌───────────────────┐
//! │  5. CodeGen       │ Emit Rust source
//! └─────────┬─────────┘
//!           ▼
//!     Rust Source
//! ```
//!
//! # Compilation Functions
//!
//! | Function | Analysis | Use Case |
//! |----------|----------|----------|
//! | [`compile_to_rust`] | Escape only | Basic compilation |
//! | [`compile_to_rust_checked`] | Escape + Ownership | Use with `--check` flag |
//! | `compile_to_rust_verified` | All + Z3 | Formal verification (requires `verification` feature) |
//! | [`compile_project`] | Multi-file | Projects with imports |
//! | [`compile_and_run`] | Full + Execute | Development workflow |
//!
//! # Examples
//!
//! ## Basic Compilation
//!
//! ```
//! # use logicaffeine_compile::compile::compile_to_rust;
//! # use logicaffeine_compile::ParseError;
//! # fn main() -> Result<(), ParseError> {
//! let source = "## Main\nLet x be 5.\nShow x.";
//! let rust_code = compile_to_rust(source)?;
//! // rust_code contains:
//! // fn main() {
//! //     let x = 5;
//! //     println!("{}", x);
//! // }
//! # Ok(())
//! # }
//! ```
//!
//! ## With Ownership Checking
//!
//! ```
//! # use logicaffeine_compile::compile::compile_to_rust_checked;
//! let source = "## Main\nLet x be 5.\nGive x to y.\nShow x.";
//! let result = compile_to_rust_checked(source);
//! // Returns Err: "x has already been given away"
//! ```

use std::collections::{HashMap, HashSet};
use std::fs;
use std::io::Write;
use std::path::Path;
use std::process::Command;

// Runtime crates paths (relative to workspace root)
const CRATES_DATA_PATH: &str = "crates/logicaffeine_data";
const CRATES_SYSTEM_PATH: &str = "crates/logicaffeine_system";

use std::fmt::Write as FmtWrite;

use crate::analysis::{DiscoveryPass, EscapeChecker, OwnershipChecker, PolicyRegistry};
use crate::arena::Arena;
use crate::arena_ctx::AstContext;
use crate::ast::{Expr, MatchArm, Stmt, TypeExpr};
use crate::ast::stmt::{BinaryOpKind, ClosureBody, Literal, Pattern, ReadSource, SelectBranch, StringPart};
use crate::codegen::{codegen_program, generate_c_header, generate_python_bindings, generate_typescript_bindings};
use crate::diagnostic::{parse_rustc_json, translate_diagnostics, LogosError};
use crate::drs::WorldState;
use crate::error::ParseError;
use crate::intern::Interner;
use crate::lexer::Lexer;
use crate::parser::Parser;
use crate::sourcemap::SourceMap;

/// A declared external crate dependency from a `## Requires` block.
#[derive(Debug, Clone)]
pub struct CrateDependency {
    pub name: String,
    pub version: String,
    pub features: Vec<String>,
}

/// Full compilation output including generated Rust code and extracted dependencies.
#[derive(Debug)]
pub struct CompileOutput {
    pub rust_code: String,
    pub dependencies: Vec<CrateDependency>,
    /// Generated C header content (populated when C exports exist).
    pub c_header: Option<String>,
    /// Generated Python ctypes bindings (populated when C exports exist).
    pub python_bindings: Option<String>,
    /// Generated TypeScript type declarations (.d.ts content, populated when C exports exist).
    pub typescript_types: Option<String>,
    /// Generated TypeScript FFI bindings (.js content, populated when C exports exist).
    pub typescript_bindings: Option<String>,
}

/// Interpret LOGOS source and return output as a string.
///
/// Runs the full pipeline (lex → discovery → parse → interpret) without
/// generating Rust code. Useful for sub-second feedback during development.
///
/// # Arguments
///
/// * `source` - LOGOS source code as a string
///
/// # Returns
///
/// The collected output from `Show` statements, joined by newlines.
///
/// # Errors
///
/// Returns [`ParseError`] if parsing fails or the interpreter encounters
/// a runtime error.
pub fn interpret_program(source: &str) -> Result<String, ParseError> {
    let result = crate::ui_bridge::interpret_for_ui_sync(source);
    if let Some(err) = result.error {
        Err(ParseError {
            kind: crate::error::ParseErrorKind::Custom(err),
            span: crate::token::Span::default(),
        })
    } else {
        Ok(result.lines.join("\n"))
    }
}

/// Compile LOGOS source to Rust source code.
///
/// This is the basic compilation function that runs lexing, parsing, and
/// escape analysis before generating Rust code.
///
/// # Arguments
///
/// * `source` - LOGOS source code as a string
///
/// # Returns
///
/// Generated Rust source code on success.
///
/// # Errors
///
/// Returns [`ParseError`] if:
/// - Lexical analysis fails (invalid tokens)
/// - Parsing fails (syntax errors)
/// - Escape analysis fails (zone-local values escaping)
///
/// # Example
///
/// ```
/// # use logicaffeine_compile::compile::compile_to_rust;
/// # use logicaffeine_compile::ParseError;
/// # fn main() -> Result<(), ParseError> {
/// let source = "## Main\nLet x be 5.\nShow x.";
/// let rust_code = compile_to_rust(source)?;
/// assert!(rust_code.contains("let x = 5;"));
/// # Ok(())
/// # }
/// ```
pub fn compile_to_rust(source: &str) -> Result<String, ParseError> {
    compile_program_full(source).map(|o| o.rust_code)
}

/// Compile LOGOS source to C code (benchmark-only subset).
///
/// Produces a self-contained C file with embedded runtime that can be
/// compiled with `gcc -O2 -o program output.c`.
pub fn compile_to_c(source: &str) -> Result<String, ParseError> {
    let mut interner = Interner::new();
    let mut lexer = Lexer::new(source, &mut interner);
    let tokens = lexer.tokenize();

    let (type_registry, _policy_registry) = {
        let mut discovery = DiscoveryPass::new(&tokens, &mut interner);
        let result = discovery.run_full();
        (result.types, result.policies)
    };
    let codegen_registry = type_registry.clone();

    let mut world_state = WorldState::new();
    let expr_arena = Arena::new();
    let term_arena = Arena::new();
    let np_arena = Arena::new();
    let sym_arena = Arena::new();
    let role_arena = Arena::new();
    let pp_arena = Arena::new();
    let stmt_arena: Arena<Stmt> = Arena::new();
    let imperative_expr_arena: Arena<Expr> = Arena::new();
    let type_expr_arena: Arena<TypeExpr> = Arena::new();

    let ast_ctx = AstContext::with_types(
        &expr_arena, &term_arena, &np_arena, &sym_arena,
        &role_arena, &pp_arena, &stmt_arena, &imperative_expr_arena,
        &type_expr_arena,
    );

    let mut parser = Parser::new(tokens, &mut world_state, &mut interner, ast_ctx, type_registry);
    let stmts = parser.parse_program()?;
    let stmts = crate::optimize::optimize_program(stmts, &imperative_expr_arena, &stmt_arena, &mut interner);

    Ok(crate::codegen_c::codegen_program_c(&stmts, &codegen_registry, &interner))
}

/// Compile LOGOS source and return full output including dependency metadata.
///
/// This is the primary compilation entry point that returns both the generated
/// Rust code and any crate dependencies declared in `## Requires` blocks.
pub fn compile_program_full(source: &str) -> Result<CompileOutput, ParseError> {
    let mut interner = Interner::new();
    let mut lexer = Lexer::new(source, &mut interner);
    let tokens = lexer.tokenize();

    // Pass 1: Discovery - scan for type definitions and policies
    let (type_registry, policy_registry) = {
        let mut discovery = DiscoveryPass::new(&tokens, &mut interner);
        let result = discovery.run_full();
        (result.types, result.policies)
    };
    // Clone for codegen (parser takes ownership)
    let codegen_registry = type_registry.clone();
    let codegen_policies = policy_registry.clone();

    let mut world_state = WorldState::new();
    let expr_arena = Arena::new();
    let term_arena = Arena::new();
    let np_arena = Arena::new();
    let sym_arena = Arena::new();
    let role_arena = Arena::new();
    let pp_arena = Arena::new();
    let stmt_arena: Arena<Stmt> = Arena::new();
    let imperative_expr_arena: Arena<Expr> = Arena::new();
    let type_expr_arena: Arena<TypeExpr> = Arena::new();

    let ast_ctx = AstContext::with_types(
        &expr_arena,
        &term_arena,
        &np_arena,
        &sym_arena,
        &role_arena,
        &pp_arena,
        &stmt_arena,
        &imperative_expr_arena,
        &type_expr_arena,
    );

    // Pass 2: Parse with type context
    let mut parser = Parser::new(tokens, &mut world_state, &mut interner, ast_ctx, type_registry);
    // Note: Don't call process_block_headers() - parse_program handles blocks itself

    let stmts = parser.parse_program()?;

    // Pass 2.5: Optimization - constant folding and dead code elimination
    let stmts = crate::optimize::optimize_program(stmts, &imperative_expr_arena, &stmt_arena, &mut interner);

    // Extract dependencies before escape analysis
    let mut dependencies = extract_dependencies(&stmts, &interner)?;

    // FFI: Auto-inject wasm-bindgen dependency if any function is exported for WASM
    let needs_wasm_bindgen = stmts.iter().any(|stmt| {
        if let Stmt::FunctionDef { is_exported: true, export_target: Some(target), .. } = stmt {
            interner.resolve(*target).eq_ignore_ascii_case("wasm")
        } else {
            false
        }
    });
    if needs_wasm_bindgen && !dependencies.iter().any(|d| d.name == "wasm-bindgen") {
        dependencies.push(CrateDependency {
            name: "wasm-bindgen".to_string(),
            version: "0.2".to_string(),
            features: vec![],
        });
    }

    // Pass 3: Escape analysis - check for zone escape violations
    // This catches obvious cases like returning zone-local variables
    let mut escape_checker = EscapeChecker::new(&interner);
    escape_checker.check_program(&stmts).map_err(|e| {
        // Convert EscapeError to ParseError for now
        // The error message is already Socratic from EscapeChecker
        ParseError {
            kind: crate::error::ParseErrorKind::Custom(e.to_string()),
            span: e.span,
        }
    })?;

    // Note: Static verification is available when the `verification` feature is enabled,
    // but must be explicitly invoked via compile_to_rust_verified().

    let type_env = crate::analysis::check_program(&stmts, &interner, &codegen_registry)
        .map_err(|e| ParseError {
            kind: e.to_parse_error_kind(&interner),
            span: crate::token::Span::default(),
        })?;
    let rust_code = codegen_program(&stmts, &codegen_registry, &codegen_policies, &interner, &type_env);

    // Universal ABI: Generate C header + bindings if any C exports exist
    let has_c = stmts.iter().any(|stmt| {
        if let Stmt::FunctionDef { is_exported: true, export_target, .. } = stmt {
            match export_target {
                None => true,
                Some(t) => interner.resolve(*t).eq_ignore_ascii_case("c"),
            }
        } else {
            false
        }
    });

    let c_header = if has_c {
        Some(generate_c_header(&stmts, "module", &interner, &codegen_registry))
    } else {
        None
    };

    // Auto-inject serde_json dependency when C exports exist (needed for collection to_json and portable struct JSON accessors)
    if has_c && !dependencies.iter().any(|d| d.name == "serde_json") {
        dependencies.push(CrateDependency {
            name: "serde_json".to_string(),
            version: "1".to_string(),
            features: vec![],
        });
    }

    let python_bindings = if has_c {
        Some(generate_python_bindings(&stmts, "module", &interner, &codegen_registry))
    } else {
        None
    };

    let (typescript_bindings, typescript_types) = if has_c {
        let (js, dts) = generate_typescript_bindings(&stmts, "module", &interner, &codegen_registry);
        (Some(js), Some(dts))
    } else {
        (None, None)
    };

    Ok(CompileOutput { rust_code, dependencies, c_header, python_bindings, typescript_types, typescript_bindings })
}

/// Extract crate dependencies from `Stmt::Require` nodes.
///
/// Deduplicates by crate name: same name + same version keeps one copy.
/// Same name + different version returns a `ParseError`.
/// Preserves declaration order (first occurrence wins).
fn extract_dependencies(stmts: &[Stmt], interner: &Interner) -> Result<Vec<CrateDependency>, ParseError> {
    use std::collections::HashMap;

    let mut seen: HashMap<String, String> = HashMap::new(); // name → version
    let mut deps: Vec<CrateDependency> = Vec::new();

    for stmt in stmts {
        if let Stmt::Require { crate_name, version, features, span } = stmt {
            let name = interner.resolve(*crate_name).to_string();
            let ver = interner.resolve(*version).to_string();

            if let Some(existing_ver) = seen.get(&name) {
                if *existing_ver != ver {
                    return Err(ParseError {
                        kind: crate::error::ParseErrorKind::Custom(format!(
                            "Conflicting versions for crate \"{}\": \"{}\" and \"{}\".",
                            name, existing_ver, ver
                        )),
                        span: *span,
                    });
                }
                // Same name + same version: skip duplicate
            } else {
                seen.insert(name.clone(), ver.clone());
                deps.push(CrateDependency {
                    name,
                    version: ver,
                    features: features.iter().map(|f| interner.resolve(*f).to_string()).collect(),
                });
            }
        }
    }

    Ok(deps)
}

/// Compile LOGOS source to Rust with ownership checking enabled.
///
/// This runs the lightweight ownership analysis pass that catches use-after-move
/// errors with control flow awareness. The analysis is fast enough to run on
/// every keystroke in an IDE.
///
/// # Arguments
///
/// * `source` - LOGOS source code as a string
///
/// # Returns
///
/// Generated Rust source code on success.
///
/// # Errors
///
/// Returns [`ParseError`] if:
/// - Any error from [`compile_to_rust`] occurs
/// - Ownership analysis detects use-after-move
/// - Ownership analysis detects use-after-borrow violations
///
/// # Example
///
/// ```
/// # use logicaffeine_compile::compile::compile_to_rust_checked;
/// // This will fail ownership checking
/// let source = "## Main\nLet x be 5.\nGive x to y.\nShow x.";
/// let result = compile_to_rust_checked(source);
/// assert!(result.is_err()); // "x has already been given away"
/// ```
///
/// # Use Case
///
/// Use this function with the `--check` CLI flag for instant feedback on
/// ownership errors before running the full Rust compilation.
pub fn compile_to_rust_checked(source: &str) -> Result<String, ParseError> {
    let mut interner = Interner::new();
    let mut lexer = Lexer::new(source, &mut interner);
    let tokens = lexer.tokenize();

    // Pass 1: Discovery - scan for type definitions and policies
    let (type_registry, policy_registry) = {
        let mut discovery = DiscoveryPass::new(&tokens, &mut interner);
        let result = discovery.run_full();
        (result.types, result.policies)
    };
    // Clone for codegen (parser takes ownership)
    let codegen_registry = type_registry.clone();
    let codegen_policies = policy_registry.clone();

    let mut world_state = WorldState::new();
    let expr_arena = Arena::new();
    let term_arena = Arena::new();
    let np_arena = Arena::new();
    let sym_arena = Arena::new();
    let role_arena = Arena::new();
    let pp_arena = Arena::new();
    let stmt_arena: Arena<Stmt> = Arena::new();
    let imperative_expr_arena: Arena<Expr> = Arena::new();
    let type_expr_arena: Arena<TypeExpr> = Arena::new();

    let ast_ctx = AstContext::with_types(
        &expr_arena,
        &term_arena,
        &np_arena,
        &sym_arena,
        &role_arena,
        &pp_arena,
        &stmt_arena,
        &imperative_expr_arena,
        &type_expr_arena,
    );

    // Pass 2: Parse with type context
    let mut parser = Parser::new(tokens, &mut world_state, &mut interner, ast_ctx, type_registry);
    let stmts = parser.parse_program()?;

    // Pass 2.5: Optimization - constant folding, propagation, and dead code elimination
    let stmts = crate::optimize::optimize_program(stmts, &imperative_expr_arena, &stmt_arena, &mut interner);

    // Pass 3: Escape analysis
    let mut escape_checker = EscapeChecker::new(&interner);
    escape_checker.check_program(&stmts).map_err(|e| {
        ParseError {
            kind: crate::error::ParseErrorKind::Custom(e.to_string()),
            span: e.span,
        }
    })?;

    // Pass 4: Ownership analysis
    // Catches use-after-move errors with control flow awareness
    let mut ownership_checker = OwnershipChecker::new(&interner);
    ownership_checker.check_program(&stmts).map_err(|e| {
        ParseError {
            kind: crate::error::ParseErrorKind::Custom(e.to_string()),
            span: e.span,
        }
    })?;

    let type_env = crate::analysis::check_program(&stmts, &interner, &codegen_registry)
        .map_err(|e| ParseError {
            kind: e.to_parse_error_kind(&interner),
            span: crate::token::Span::default(),
        })?;
    let rust_code = codegen_program(&stmts, &codegen_registry, &codegen_policies, &interner, &type_env);

    Ok(rust_code)
}

/// Compile LOGOS source to Rust with full Z3 static verification.
///
/// This runs the Z3-based verifier on Assert statements before code generation,
/// proving that assertions hold for all possible inputs. This is the most
/// thorough compilation mode, suitable for high-assurance code.
///
/// # Arguments
///
/// * `source` - LOGOS source code as a string
///
/// # Returns
///
/// Generated Rust source code on success.
///
/// # Errors
///
/// Returns [`ParseError`] if:
/// - Any error from [`compile_to_rust`] occurs
/// - Z3 cannot prove an Assert statement
/// - Refinement type constraints cannot be satisfied
/// - Termination cannot be proven for loops with `decreasing`
///
/// # Example
///
/// ```no_run
/// # use logicaffeine_compile::compile::compile_to_rust_verified;
/// # use logicaffeine_compile::ParseError;
/// # fn main() -> Result<(), ParseError> {
/// let source = r#"
/// ## Main
/// Let x: { it: Int | it > 0 } be 5.
/// Assert that x > 0.
/// "#;
/// let rust_code = compile_to_rust_verified(source)?;
/// # Ok(())
/// # }
/// ```
///
/// # Feature Flag
///
/// This function requires the `verification` feature to be enabled:
///
/// ```toml
/// [dependencies]
/// logicaffeine_compile = { version = "...", features = ["verification"] }
/// ```
#[cfg(feature = "verification")]
pub fn compile_to_rust_verified(source: &str) -> Result<String, ParseError> {
    use crate::verification::VerificationPass;

    let mut interner = Interner::new();
    let mut lexer = Lexer::new(source, &mut interner);
    let tokens = lexer.tokenize();

    // Pass 1: Discovery - scan for type definitions and policies
    let (type_registry, policy_registry) = {
        let mut discovery = DiscoveryPass::new(&tokens, &mut interner);
        let result = discovery.run_full();
        (result.types, result.policies)
    };
    // Clone for codegen (parser takes ownership)
    let codegen_registry = type_registry.clone();
    let codegen_policies = policy_registry.clone();

    let mut world_state = WorldState::new();
    let expr_arena = Arena::new();
    let term_arena = Arena::new();
    let np_arena = Arena::new();
    let sym_arena = Arena::new();
    let role_arena = Arena::new();
    let pp_arena = Arena::new();
    let stmt_arena: Arena<Stmt> = Arena::new();
    let imperative_expr_arena: Arena<Expr> = Arena::new();
    let type_expr_arena: Arena<TypeExpr> = Arena::new();

    let ast_ctx = AstContext::with_types(
        &expr_arena,
        &term_arena,
        &np_arena,
        &sym_arena,
        &role_arena,
        &pp_arena,
        &stmt_arena,
        &imperative_expr_arena,
        &type_expr_arena,
    );

    // Pass 2: Parse with type context
    let mut parser = Parser::new(tokens, &mut world_state, &mut interner, ast_ctx, type_registry);
    let stmts = parser.parse_program()?;

    // Pass 3: Escape analysis
    let mut escape_checker = EscapeChecker::new(&interner);
    escape_checker.check_program(&stmts).map_err(|e| {
        ParseError {
            kind: crate::error::ParseErrorKind::Custom(e.to_string()),
            span: e.span,
        }
    })?;

    // Pass 4: Static verification
    let mut verifier = VerificationPass::new(&interner);
    verifier.verify_program(&stmts).map_err(|e| {
        ParseError {
            kind: crate::error::ParseErrorKind::Custom(format!(
                "Verification Failed:\n\n{}",
                e
            )),
            span: crate::token::Span::default(),
        }
    })?;

    let type_env = crate::analysis::check_program(&stmts, &interner, &codegen_registry)
        .map_err(|e| ParseError {
            kind: e.to_parse_error_kind(&interner),
            span: crate::token::Span::default(),
        })?;
    let rust_code = codegen_program(&stmts, &codegen_registry, &codegen_policies, &interner, &type_env);

    Ok(rust_code)
}

/// Compile LOGOS source and write output to a directory as a Cargo project.
///
/// Creates a complete Cargo project structure with:
/// - `src/main.rs` containing the generated Rust code
/// - `Cargo.toml` with runtime dependencies
/// - `crates/` directory with runtime crate copies
///
/// # Arguments
///
/// * `source` - LOGOS source code as a string
/// * `output_dir` - Directory to create the Cargo project in
///
/// # Errors
///
/// Returns [`CompileError`] if:
/// - Compilation fails (wrapped as `CompileError::Parse`)
/// - File system operations fail (wrapped as `CompileError::Io`)
///
/// # Example
///
/// ```no_run
/// # use logicaffeine_compile::compile::{compile_to_dir, CompileError};
/// # use std::path::Path;
/// # fn main() -> Result<(), CompileError> {
/// let source = "## Main\nShow \"Hello\".";
/// compile_to_dir(source, Path::new("/tmp/my_project"))?;
/// // Now /tmp/my_project is a buildable Cargo project
/// # Ok(())
/// # }
/// ```
pub fn compile_to_dir(source: &str, output_dir: &Path) -> Result<(), CompileError> {
    let output = compile_program_full(source).map_err(CompileError::Parse)?;

    // Create output directory structure
    let src_dir = output_dir.join("src");
    fs::create_dir_all(&src_dir).map_err(|e| CompileError::Io(e.to_string()))?;

    // Write main.rs (codegen already includes the use statements)
    let main_path = src_dir.join("main.rs");
    let mut file = fs::File::create(&main_path).map_err(|e| CompileError::Io(e.to_string()))?;
    file.write_all(output.rust_code.as_bytes()).map_err(|e| CompileError::Io(e.to_string()))?;

    // Write Cargo.toml with runtime crate dependencies
    let mut cargo_toml = String::from(r#"[package]
name = "logos_output"
version = "0.1.0"
edition = "2021"

[dependencies]
logicaffeine-data = { path = "./crates/logicaffeine_data" }
logicaffeine-system = { path = "./crates/logicaffeine_system", features = ["full"] }
tokio = { version = "1", features = ["rt-multi-thread", "macros"] }

[target.'cfg(target_os = "linux")'.dependencies]
logicaffeine-system = { path = "./crates/logicaffeine_system", features = ["full", "io-uring"] }
"#);

    // Append user-declared dependencies from ## Requires blocks
    for dep in &output.dependencies {
        if dep.features.is_empty() {
            let _ = writeln!(cargo_toml, "{} = \"{}\"", dep.name, dep.version);
        } else {
            let feats = dep.features.iter()
                .map(|f| format!("\"{}\"", f))
                .collect::<Vec<_>>()
                .join(", ");
            let _ = writeln!(
                cargo_toml,
                "{} = {{ version = \"{}\", features = [{}] }}",
                dep.name, dep.version, feats
            );
        }
    }

    cargo_toml.push_str("\n[profile.release]\nlto = true\nopt-level = 3\ncodegen-units = 1\npanic = \"abort\"\nstrip = true\n");

    let cargo_path = output_dir.join("Cargo.toml");
    let mut file = fs::File::create(&cargo_path).map_err(|e| CompileError::Io(e.to_string()))?;
    file.write_all(cargo_toml.as_bytes()).map_err(|e| CompileError::Io(e.to_string()))?;

    // Write .cargo/config.toml with target-cpu=native for optimal codegen.
    // Enables SIMD auto-vectorization and CPU-specific instruction selection.
    let cargo_config_dir = output_dir.join(".cargo");
    fs::create_dir_all(&cargo_config_dir).map_err(|e| CompileError::Io(e.to_string()))?;
    let config_content = "[build]\nrustflags = [\"-C\", \"target-cpu=native\"]\n";
    let config_path = cargo_config_dir.join("config.toml");
    fs::write(&config_path, config_content).map_err(|e| CompileError::Io(e.to_string()))?;

    // Copy runtime crates to output directory
    copy_runtime_crates(output_dir)?;

    Ok(())
}

/// Copy the runtime crates to the output directory.
/// Copies logicaffeine_data and logicaffeine_system.
pub fn copy_runtime_crates(output_dir: &Path) -> Result<(), CompileError> {
    let crates_dir = output_dir.join("crates");
    fs::create_dir_all(&crates_dir).map_err(|e| CompileError::Io(e.to_string()))?;

    // Find workspace root
    let workspace_root = find_workspace_root()?;

    // Copy logicaffeine_data
    let data_src = workspace_root.join(CRATES_DATA_PATH);
    let data_dest = crates_dir.join("logicaffeine_data");
    copy_dir_recursive(&data_src, &data_dest)?;
    deworkspace_cargo_toml(&data_dest.join("Cargo.toml"))?;

    // Copy logicaffeine_system
    let system_src = workspace_root.join(CRATES_SYSTEM_PATH);
    let system_dest = crates_dir.join("logicaffeine_system");
    copy_dir_recursive(&system_src, &system_dest)?;
    deworkspace_cargo_toml(&system_dest.join("Cargo.toml"))?;

    // Also need to copy logicaffeine_base since both crates depend on it
    let base_src = workspace_root.join("crates/logicaffeine_base");
    let base_dest = crates_dir.join("logicaffeine_base");
    copy_dir_recursive(&base_src, &base_dest)?;
    deworkspace_cargo_toml(&base_dest.join("Cargo.toml"))?;

    Ok(())
}

/// Resolve workspace-inherited fields in a copied crate's Cargo.toml.
///
/// When runtime crates are copied to a standalone project, any fields using
/// `*.workspace = true` won't resolve because there's no parent workspace.
/// This rewrites them with concrete values (matching the workspace's settings).
fn deworkspace_cargo_toml(cargo_toml_path: &Path) -> Result<(), CompileError> {
    let content = fs::read_to_string(cargo_toml_path)
        .map_err(|e| CompileError::Io(e.to_string()))?;

    let mut result = String::with_capacity(content.len());
    for line in content.lines() {
        let trimmed = line.trim();
        if trimmed == "edition.workspace = true" {
            result.push_str("edition = \"2021\"");
        } else if trimmed == "rust-version.workspace = true" {
            result.push_str("rust-version = \"1.75\"");
        } else if trimmed == "authors.workspace = true"
            || trimmed == "repository.workspace = true"
            || trimmed == "homepage.workspace = true"
            || trimmed == "documentation.workspace = true"
            || trimmed == "keywords.workspace = true"
            || trimmed == "categories.workspace = true"
            || trimmed == "license.workspace = true"
        {
            // Drop these lines — they're metadata not needed for compilation
            continue;
        } else if trimmed.contains(".workspace = true") {
            // Catch-all: drop any other workspace-inherited fields
            continue;
        } else {
            result.push_str(line);
        }
        result.push('\n');
    }

    fs::write(cargo_toml_path, result)
        .map_err(|e| CompileError::Io(e.to_string()))?;

    Ok(())
}

/// Find the workspace root directory.
fn find_workspace_root() -> Result<std::path::PathBuf, CompileError> {
    // 1. Explicit override via LOGOS_WORKSPACE env var
    if let Ok(workspace) = std::env::var("LOGOS_WORKSPACE") {
        let path = Path::new(&workspace);
        if path.join("Cargo.toml").exists() && path.join("crates").exists() {
            return Ok(path.to_path_buf());
        }
    }

    // 2. Try CARGO_MANIFEST_DIR (works during cargo build of largo itself)
    if let Ok(manifest_dir) = std::env::var("CARGO_MANIFEST_DIR") {
        let path = Path::new(&manifest_dir);
        if let Some(parent) = path.parent().and_then(|p| p.parent()) {
            if parent.join("Cargo.toml").exists() {
                return Ok(parent.to_path_buf());
            }
        }
    }

    // 3. Infer from the largo binary's own location
    //    e.g. /workspace/target/release/largo → /workspace
    if let Ok(exe) = std::env::current_exe() {
        if let Some(dir) = exe.parent() {
            // Walk up from the binary's directory
            let mut candidate = dir.to_path_buf();
            for _ in 0..5 {
                if candidate.join("Cargo.toml").exists() && candidate.join("crates").exists() {
                    return Ok(candidate);
                }
                if !candidate.pop() {
                    break;
                }
            }
        }
    }

    // 4. Fallback to current directory traversal
    let mut current = std::env::current_dir()
        .map_err(|e| CompileError::Io(e.to_string()))?;

    loop {
        if current.join("Cargo.toml").exists() && current.join("crates").exists() {
            return Ok(current);
        }
        if !current.pop() {
            return Err(CompileError::Io(
                "Could not find workspace root. Set LOGOS_WORKSPACE env var or run from within the workspace.".to_string()
            ));
        }
    }
}

/// Recursively copy a directory.
/// Skips files that disappear during copy (race condition with parallel builds).
fn copy_dir_recursive(src: &Path, dst: &Path) -> Result<(), CompileError> {
    fs::create_dir_all(dst).map_err(|e| CompileError::Io(e.to_string()))?;

    for entry in fs::read_dir(src).map_err(|e| CompileError::Io(e.to_string()))? {
        let entry = entry.map_err(|e| CompileError::Io(e.to_string()))?;
        let src_path = entry.path();
        let file_name = entry.file_name();
        let dst_path = dst.join(&file_name);

        // Skip target directory, build artifacts, and lock files
        if file_name == "target"
            || file_name == ".git"
            || file_name == "Cargo.lock"
            || file_name == ".DS_Store"
        {
            continue;
        }

        // Skip files that start with a dot (hidden files)
        if file_name.to_string_lossy().starts_with('.') {
            continue;
        }

        // Check if path still exists (race condition protection)
        if !src_path.exists() {
            continue;
        }

        if src_path.is_dir() {
            copy_dir_recursive(&src_path, &dst_path)?;
        } else if file_name == "Cargo.toml" {
            // Special handling for Cargo.toml: remove [workspace] line
            // which can interfere with nested crate dependencies
            match fs::read_to_string(&src_path) {
                Ok(content) => {
                    let filtered: String = content
                        .lines()
                        .filter(|line| !line.trim().starts_with("[workspace]"))
                        .collect::<Vec<_>>()
                        .join("\n");
                    fs::write(&dst_path, filtered)
                        .map_err(|e| CompileError::Io(e.to_string()))?;
                }
                Err(e) if e.kind() == std::io::ErrorKind::NotFound => continue,
                Err(e) => return Err(CompileError::Io(e.to_string())),
            }
        } else {
            match fs::copy(&src_path, &dst_path) {
                Ok(_) => {}
                Err(e) if e.kind() == std::io::ErrorKind::NotFound => continue,
                Err(e) => return Err(CompileError::Io(e.to_string())),
            }
        }
    }

    Ok(())
}

/// Compile and run a LOGOS program end-to-end.
///
/// This function performs the full compilation workflow:
/// 1. Compile LOGOS to Rust via [`compile_to_dir`]
/// 2. Run `cargo build` with JSON diagnostics
/// 3. Translate any rustc errors to LOGOS-friendly messages
/// 4. Run the compiled program via `cargo run`
///
/// # Arguments
///
/// * `source` - LOGOS source code as a string
/// * `output_dir` - Directory to create the temporary Cargo project in
///
/// # Returns
///
/// The stdout output of the executed program.
///
/// # Errors
///
/// Returns [`CompileError`] if:
/// - Compilation fails (see [`compile_to_dir`])
/// - Rust compilation fails (`CompileError::Build` or `CompileError::Ownership`)
/// - The program crashes at runtime (`CompileError::Runtime`)
///
/// # Diagnostic Translation
///
/// When rustc reports errors (e.g., E0382 for use-after-move), this function
/// uses the [`diagnostic`](crate::diagnostic) module to translate them into
/// LOGOS-friendly Socratic error messages.
///
/// # Example
///
/// ```no_run
/// # use logicaffeine_compile::compile::{compile_and_run, CompileError};
/// # use std::path::Path;
/// # fn main() -> Result<(), CompileError> {
/// let source = "## Main\nShow \"Hello, World!\".";
/// let output = compile_and_run(source, Path::new("/tmp/run"))?;
/// assert_eq!(output.trim(), "Hello, World!");
/// # Ok(())
/// # }
/// ```
pub fn compile_and_run(source: &str, output_dir: &Path) -> Result<String, CompileError> {
    // Pre-check: catch ownership errors (use-after-move) with friendly messages
    // before codegen runs (codegen defensively clones, masking these errors)
    compile_to_rust_checked(source).map_err(CompileError::Parse)?;

    compile_to_dir(source, output_dir)?;

    // Run cargo build with JSON message format for structured error parsing
    let build_output = Command::new("cargo")
        .arg("build")
        .arg("--message-format=json")
        .current_dir(output_dir)
        .output()
        .map_err(|e| CompileError::Io(e.to_string()))?;

    if !build_output.status.success() {
        let stderr = String::from_utf8_lossy(&build_output.stderr);
        let stdout = String::from_utf8_lossy(&build_output.stdout);

        // Try to parse JSON diagnostics and translate them
        let diagnostics = parse_rustc_json(&stdout);

        if !diagnostics.is_empty() {
            // Create a basic source map with the LOGOS source
            let source_map = SourceMap::new(source.to_string());
            let interner = Interner::new();

            if let Some(logos_error) = translate_diagnostics(&diagnostics, &source_map, &interner) {
                return Err(CompileError::Ownership(logos_error));
            }
        }

        // Fallback to raw error if translation fails
        return Err(CompileError::Build(stderr.to_string()));
    }

    // Run the compiled program
    let run_output = Command::new("cargo")
        .arg("run")
        .arg("--quiet")
        .current_dir(output_dir)
        .output()
        .map_err(|e| CompileError::Io(e.to_string()))?;

    if !run_output.status.success() {
        let stderr = String::from_utf8_lossy(&run_output.stderr);
        return Err(CompileError::Runtime(stderr.to_string()));
    }

    let stdout = String::from_utf8_lossy(&run_output.stdout);
    Ok(stdout.to_string())
}

/// Compile a LOGOS source file.
/// For single-file compilation without dependencies.
pub fn compile_file(path: &Path) -> Result<String, CompileError> {
    let source = fs::read_to_string(path).map_err(|e| CompileError::Io(e.to_string()))?;
    compile_to_rust(&source).map_err(CompileError::Parse)
}

/// Compile a multi-file LOGOS project with dependency resolution.
///
/// This function:
/// 1. Reads the entry file
/// 2. Scans for dependencies in the abstract (Markdown links)
/// 3. Recursively loads and discovers types from dependencies
/// 4. Compiles with the combined type registry
///
/// # Arguments
/// * `entry_file` - The main entry file to compile (root is derived from parent directory)
///
/// # Example
/// ```no_run
/// # use logicaffeine_compile::compile::compile_project;
/// # use std::path::Path;
/// let result = compile_project(Path::new("/project/main.md"));
/// ```
pub fn compile_project(entry_file: &Path) -> Result<CompileOutput, CompileError> {
    use crate::loader::Loader;
    use crate::analysis::discover_with_imports;

    let root_path = entry_file.parent().unwrap_or(Path::new(".")).to_path_buf();
    let mut loader = Loader::new(root_path);
    let mut interner = Interner::new();

    // Read the entry file
    let source = fs::read_to_string(entry_file)
        .map_err(|e| CompileError::Io(format!("Failed to read entry file: {}", e)))?;

    // Discover types from entry file and all imports
    let type_registry = discover_with_imports(entry_file, &source, &mut loader, &mut interner)
        .map_err(|e| CompileError::Io(e))?;

    // Now compile with the discovered types
    compile_to_rust_with_registry_full(&source, type_registry, &mut interner)
        .map_err(CompileError::Parse)
}

/// Compile LOGOS source with a pre-populated type registry, returning full output.
/// Returns both generated Rust code and extracted dependencies.
fn compile_to_rust_with_registry_full(
    source: &str,
    type_registry: crate::analysis::TypeRegistry,
    interner: &mut Interner,
) -> Result<CompileOutput, ParseError> {
    let mut lexer = Lexer::new(source, interner);
    let tokens = lexer.tokenize();

    // Discovery pass for policies (types already discovered)
    let policy_registry = {
        let mut discovery = DiscoveryPass::new(&tokens, interner);
        discovery.run_full().policies
    };

    let codegen_registry = type_registry.clone();
    let codegen_policies = policy_registry.clone();

    let mut world_state = WorldState::new();
    let expr_arena = Arena::new();
    let term_arena = Arena::new();
    let np_arena = Arena::new();
    let sym_arena = Arena::new();
    let role_arena = Arena::new();
    let pp_arena = Arena::new();
    let stmt_arena: Arena<Stmt> = Arena::new();
    let imperative_expr_arena: Arena<Expr> = Arena::new();
    let type_expr_arena: Arena<TypeExpr> = Arena::new();

    let ast_ctx = AstContext::with_types(
        &expr_arena,
        &term_arena,
        &np_arena,
        &sym_arena,
        &role_arena,
        &pp_arena,
        &stmt_arena,
        &imperative_expr_arena,
        &type_expr_arena,
    );

    let mut parser = Parser::new(tokens, &mut world_state, interner, ast_ctx, type_registry);
    let stmts = parser.parse_program()?;

    // Extract dependencies before escape analysis
    let mut dependencies = extract_dependencies(&stmts, interner)?;

    // FFI: Auto-inject wasm-bindgen dependency if any function is exported for WASM
    let needs_wasm_bindgen = stmts.iter().any(|stmt| {
        if let Stmt::FunctionDef { is_exported: true, export_target: Some(target), .. } = stmt {
            interner.resolve(*target).eq_ignore_ascii_case("wasm")
        } else {
            false
        }
    });
    if needs_wasm_bindgen && !dependencies.iter().any(|d| d.name == "wasm-bindgen") {
        dependencies.push(CrateDependency {
            name: "wasm-bindgen".to_string(),
            version: "0.2".to_string(),
            features: vec![],
        });
    }

    let mut escape_checker = EscapeChecker::new(interner);
    escape_checker.check_program(&stmts).map_err(|e| {
        ParseError {
            kind: crate::error::ParseErrorKind::Custom(e.to_string()),
            span: e.span,
        }
    })?;

    let type_env = crate::analysis::check_program(&stmts, interner, &codegen_registry)
        .map_err(|e| ParseError {
            kind: e.to_parse_error_kind(interner),
            span: crate::token::Span::default(),
        })?;
    let rust_code = codegen_program(&stmts, &codegen_registry, &codegen_policies, interner, &type_env);

    // Universal ABI: Generate C header + bindings if any C exports exist
    let has_c = stmts.iter().any(|stmt| {
        if let Stmt::FunctionDef { is_exported: true, export_target, .. } = stmt {
            match export_target {
                None => true,
                Some(t) => interner.resolve(*t).eq_ignore_ascii_case("c"),
            }
        } else {
            false
        }
    });

    let c_header = if has_c {
        Some(generate_c_header(&stmts, "module", interner, &codegen_registry))
    } else {
        None
    };

    if has_c && !dependencies.iter().any(|d| d.name == "serde_json") {
        dependencies.push(CrateDependency {
            name: "serde_json".to_string(),
            version: "1".to_string(),
            features: vec![],
        });
    }

    let python_bindings = if has_c {
        Some(generate_python_bindings(&stmts, "module", interner, &codegen_registry))
    } else {
        None
    };

    let (typescript_bindings, typescript_types) = if has_c {
        let (js, dts) = generate_typescript_bindings(&stmts, "module", interner, &codegen_registry);
        (Some(js), Some(dts))
    } else {
        (None, None)
    };

    Ok(CompileOutput { rust_code, dependencies, c_header, python_bindings, typescript_types, typescript_bindings })
}

/// Errors that can occur during the LOGOS compilation pipeline.
///
/// This enum represents the different stages where compilation can fail,
/// from parsing through to runtime execution.
///
/// # Error Hierarchy
///
/// ```text
/// CompileError
/// ├── Parse      ← Lexing, parsing, or static analysis
/// ├── Io         ← File system operations
/// ├── Build      ← Rust compilation (cargo build)
/// ├── Ownership  ← Translated borrow checker errors
/// └── Runtime    ← Program execution failure
/// ```
///
/// # Error Translation
///
/// The `Ownership` variant contains LOGOS-friendly error messages translated
/// from rustc's borrow checker errors (E0382, E0505, E0597) using the
/// [`diagnostic`](crate::diagnostic) module.
#[derive(Debug)]
pub enum CompileError {
    /// Parsing or static analysis failed.
    ///
    /// This includes lexer errors, syntax errors, escape analysis failures,
    /// ownership analysis failures, and Z3 verification failures.
    Parse(ParseError),

    /// File system operation failed.
    ///
    /// Typically occurs when reading source files or writing output.
    Io(String),

    /// Rust compilation failed (`cargo build`).
    ///
    /// Contains the raw stderr output from rustc when diagnostic translation
    /// was not possible.
    Build(String),

    /// Runtime execution failed.
    ///
    /// Contains stderr output from the executed program.
    Runtime(String),

    /// Translated ownership/borrow checker error with LOGOS-friendly message.
    ///
    /// This variant is used when rustc reports errors like E0382 (use after move)
    /// and we can translate them into natural language error messages that
    /// reference the original LOGOS source.
    Ownership(LogosError),
}

impl std::fmt::Display for CompileError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            CompileError::Parse(e) => write!(f, "Parse error: {:?}", e),
            CompileError::Io(e) => write!(f, "IO error: {}", e),
            CompileError::Build(e) => write!(f, "Build error: {}", e),
            CompileError::Runtime(e) => write!(f, "Runtime error: {}", e),
            CompileError::Ownership(e) => write!(f, "{}", e),
        }
    }
}

impl std::error::Error for CompileError {}

// ============================================================
// Futamura Projection Support — encode_program + verify_no_overhead
// ============================================================

/// Encode a LogicAffeine program (given as source) into CProgram construction source.
///
/// Takes LogicAffeine source code (with or without `## Main` header) and returns
/// LogicAffeine source code that constructs the equivalent CProgram data structure.
/// The result defines a variable `prog` of type CProgram.
pub fn encode_program_source(source: &str) -> Result<String, ParseError> {
    let full_source = if source.contains("## Main") || source.contains("## To ") {
        source.to_string()
    } else {
        format!("## Main\n{}", source)
    };

    let mut interner = Interner::new();
    let mut lexer = Lexer::new(&full_source, &mut interner);
    let tokens = lexer.tokenize();

    let type_registry = {
        let mut discovery = DiscoveryPass::new(&tokens, &mut interner);
        let result = discovery.run_full();
        result.types
    };

    // Collect variant constructors before the parser takes ownership of type_registry
    let mut variant_constructors: HashMap<String, Vec<String>> = HashMap::new();
    for (_type_name, type_def) in type_registry.iter_types() {
        if let crate::analysis::TypeDef::Enum { variants, .. } = type_def {
            for variant in variants {
                let vname = interner.resolve(variant.name).to_string();
                let field_names: Vec<String> = variant.fields.iter()
                    .map(|f| interner.resolve(f.name).to_string())
                    .collect();
                variant_constructors.insert(vname, field_names);
            }
        }
    }

    let mut world_state = WorldState::new();
    let expr_arena = Arena::new();
    let term_arena = Arena::new();
    let np_arena = Arena::new();
    let sym_arena = Arena::new();
    let role_arena = Arena::new();
    let pp_arena = Arena::new();
    let stmt_arena: Arena<Stmt> = Arena::new();
    let imperative_expr_arena: Arena<Expr> = Arena::new();
    let type_expr_arena: Arena<TypeExpr> = Arena::new();

    let ast_ctx = AstContext::with_types(
        &expr_arena, &term_arena, &np_arena, &sym_arena,
        &role_arena, &pp_arena, &stmt_arena, &imperative_expr_arena,
        &type_expr_arena,
    );

    let mut parser = crate::parser::Parser::new(
        tokens, &mut world_state, &mut interner, ast_ctx, type_registry,
    );
    let stmts = parser.parse_program()?;

    let mut functions: Vec<(String, Vec<String>, Vec<&Stmt>)> = Vec::new();
    let mut main_stmts: Vec<&Stmt> = Vec::new();

    for stmt in &stmts {
        if let Stmt::FunctionDef { name, params, body, is_native, .. } = stmt {
            if *is_native {
                continue; // Skip native function declarations — they have no encodable body
            }
            let fn_name = interner.resolve(*name).to_string();
            let param_names: Vec<String> = params
                .iter()
                .map(|(name, _)| interner.resolve(*name).to_string())
                .collect();
            let body_stmts: Vec<&Stmt> = body.iter().collect();
            functions.push((fn_name, param_names, body_stmts));
        } else {
            main_stmts.push(stmt);
        }
    }

    let mut counter = 0usize;
    let mut output = String::new();

    // Build the funcMap directly (Map of Text to CFunc) with fixed name
    output.push_str("Let encodedFuncMap be a new Map of Text to CFunc.\n");

    for (fn_name, params, body) in &functions {
        let body_var = encode_stmt_list_src(body, &mut counter, &mut output, &interner, &variant_constructors);

        let params_var = format!("params_{}", counter);
        counter += 1;
        output.push_str(&format!("Let {} be a new Seq of Text.\n", params_var));
        for p in params {
            output.push_str(&format!("Push \"{}\" to {}.\n", p, params_var));
        }

        let func_var = format!("func_{}", counter);
        counter += 1;
        output.push_str(&format!(
            "Let {} be a new CFuncDef with name \"{}\" and params {} and body {}.\n",
            func_var, fn_name, params_var, body_var
        ));
        output.push_str(&format!(
            "Set item \"{}\" of encodedFuncMap to {}.\n",
            fn_name, func_var
        ));
    }

    // Build main statement list with fixed name
    let main_var = encode_stmt_list_src(&main_stmts, &mut counter, &mut output, &interner, &variant_constructors);
    output.push_str(&format!("Let encodedMain be {}.\n", main_var));

    Ok(output)
}

/// Compact encoding: inlines simple expressions (literals, variables) to reduce
/// encoding size by ~3x. Same semantics as encode_program_source but produces
/// fewer Let statements.
pub fn encode_program_source_compact(source: &str) -> Result<String, ParseError> {
    let full_source = if source.contains("## Main") || source.contains("## To ") {
        source.to_string()
    } else {
        format!("## Main\n{}", source)
    };

    let mut interner = Interner::new();
    let mut lexer = Lexer::new(&full_source, &mut interner);
    let tokens = lexer.tokenize();

    let type_registry = {
        let mut discovery = DiscoveryPass::new(&tokens, &mut interner);
        let result = discovery.run_full();
        result.types
    };

    let mut variant_constructors: HashMap<String, Vec<String>> = HashMap::new();
    for (_type_name, type_def) in type_registry.iter_types() {
        if let crate::analysis::TypeDef::Enum { variants, .. } = type_def {
            for variant in variants {
                let vname = interner.resolve(variant.name).to_string();
                let field_names: Vec<String> = variant.fields.iter()
                    .map(|f| interner.resolve(f.name).to_string())
                    .collect();
                variant_constructors.insert(vname, field_names);
            }
        }
    }

    let mut world_state = WorldState::new();
    let expr_arena = Arena::new();
    let term_arena = Arena::new();
    let np_arena = Arena::new();
    let sym_arena = Arena::new();
    let role_arena = Arena::new();
    let pp_arena = Arena::new();
    let stmt_arena: Arena<Stmt> = Arena::new();
    let imperative_expr_arena: Arena<Expr> = Arena::new();
    let type_expr_arena: Arena<TypeExpr> = Arena::new();

    let ast_ctx = AstContext::with_types(
        &expr_arena, &term_arena, &np_arena, &sym_arena,
        &role_arena, &pp_arena, &stmt_arena, &imperative_expr_arena,
        &type_expr_arena,
    );

    let mut parser = crate::parser::Parser::new(
        tokens, &mut world_state, &mut interner, ast_ctx, type_registry,
    );
    let stmts = parser.parse_program()?;

    let mut functions: Vec<(String, Vec<String>, Vec<&Stmt>)> = Vec::new();
    let mut main_stmts: Vec<&Stmt> = Vec::new();

    for stmt in &stmts {
        if let Stmt::FunctionDef { name, params, body, is_native, .. } = stmt {
            if *is_native { continue; }
            let fn_name = interner.resolve(*name).to_string();
            let param_names: Vec<String> = params
                .iter()
                .map(|(name, _)| interner.resolve(*name).to_string())
                .collect();
            let body_stmts: Vec<&Stmt> = body.iter().collect();
            functions.push((fn_name, param_names, body_stmts));
        } else {
            main_stmts.push(stmt);
        }
    }

    let mut counter = 0usize;
    let mut output = String::new();

    output.push_str("Let encodedFuncMap be a new Map of Text to CFunc.\n");

    for (fn_name, params, body) in &functions {
        let body_var = encode_stmt_list_compact(body, &mut counter, &mut output, &interner, &variant_constructors);

        let params_var = format!("params_{}", counter);
        counter += 1;
        output.push_str(&format!("Let {} be a new Seq of Text.\n", params_var));
        for p in params {
            output.push_str(&format!("Push \"{}\" to {}.\n", p, params_var));
        }

        let func_var = format!("func_{}", counter);
        counter += 1;
        output.push_str(&format!(
            "Let {} be a new CFuncDef with name \"{}\" and params {} and body {}.\n",
            func_var, fn_name, params_var, body_var
        ));
        output.push_str(&format!(
            "Set item \"{}\" of encodedFuncMap to {}.\n",
            fn_name, func_var
        ));
    }

    let main_var = encode_stmt_list_compact(&main_stmts, &mut counter, &mut output, &interner, &variant_constructors);
    output.push_str(&format!("Let encodedMain be {}.\n", main_var));

    Ok(output)
}

/// Returns an inline expression string for simple expressions (no Let variable needed).
/// Returns None for complex expressions that require a Let variable.
fn try_inline_expr(expr: &Expr, interner: &Interner) -> Option<String> {
    match expr {
        Expr::Literal(lit) => match lit {
            Literal::Number(n) => Some(format!("(a new CInt with value {})", n)),
            Literal::Boolean(b) => Some(format!("(a new CBool with value {})", b)),
            Literal::Text(s) => {
                let text = interner.resolve(*s);
                Some(format!("(a new CText with value \"{}\")", text))
            }
            Literal::Float(f) => Some(format!("(a new CFloat with value {})", f)),
            Literal::Nothing => Some("(a new CText with value \"nothing\")".to_string()),
            _ => None,
        },
        Expr::Identifier(sym) => {
            let name = interner.resolve(*sym);
            Some(format!("(a new CVar with name \"{}\")", name))
        }
        Expr::Not { operand } => {
            if let Some(inner) = try_inline_expr(operand, interner) {
                Some(format!("(a new CNot with inner {})", inner))
            } else {
                None
            }
        }
        Expr::OptionNone => Some("(a new COptionNone)".to_string()),
        _ => None,
    }
}

fn encode_expr_compact(expr: &Expr, counter: &mut usize, output: &mut String, interner: &Interner, variants: &HashMap<String, Vec<String>>) -> String {
    // Try inline first
    if let Some(inline) = try_inline_expr(expr, interner) {
        return inline;
    }

    // Fall back to Let variable (reuse encode_expr_src logic but with compact children)
    let var = format!("e_{}", *counter);
    *counter += 1;

    match expr {
        Expr::BinaryOp { op, left, right } => {
            let left_var = encode_expr_compact(left, counter, output, interner, variants);
            let right_var = encode_expr_compact(right, counter, output, interner, variants);
            let op_str = match op {
                BinaryOpKind::Add => "+",
                BinaryOpKind::Subtract => "-",
                BinaryOpKind::Multiply => "*",
                BinaryOpKind::Divide => "/",
                BinaryOpKind::Modulo => "%",
                BinaryOpKind::Eq => "==",
                BinaryOpKind::NotEq => "!=",
                BinaryOpKind::Lt => "<",
                BinaryOpKind::Gt => ">",
                BinaryOpKind::LtEq => "<=",
                BinaryOpKind::GtEq => ">=",
                BinaryOpKind::And => "&&",
                BinaryOpKind::Or => "||",
                BinaryOpKind::Concat => "+",
                BinaryOpKind::BitXor => "^",
                BinaryOpKind::Shl => "<<",
                BinaryOpKind::Shr => ">>",
            };
            output.push_str(&format!(
                "Let {} be a new CBinOp with op \"{}\" and left {} and right {}.\n",
                var, op_str, left_var, right_var
            ));
        }
        Expr::Call { function, args } => {
            let fn_name = interner.resolve(*function);
            if let Some(field_names) = variants.get(fn_name) {
                let names_var = format!("nvNames_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of Text.\n", names_var));
                let vals_var = format!("nvVals_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CExpr.\n", vals_var));
                for (i, arg) in args.iter().enumerate() {
                    let fname = field_names.get(i).map(|s| s.as_str()).unwrap_or("value");
                    output.push_str(&format!("Push \"{}\" to {}.\n", fname, names_var));
                    let arg_var = encode_expr_compact(arg, counter, output, interner, variants);
                    output.push_str(&format!("Push {} to {}.\n", arg_var, vals_var));
                }
                output.push_str(&format!(
                    "Let {} be a new CNewVariant with tag \"{}\" and fnames {} and fvals {}.\n",
                    var, fn_name, names_var, vals_var
                ));
            } else {
                let args_var = format!("callArgs_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CExpr.\n", args_var));
                for arg in args {
                    let arg_var = encode_expr_compact(arg, counter, output, interner, variants);
                    output.push_str(&format!("Push {} to {}.\n", arg_var, args_var));
                }
                output.push_str(&format!(
                    "Let {} be a new CCall with name \"{}\" and args {}.\n",
                    var, fn_name, args_var
                ));
            }
        }
        Expr::Index { collection, index } => {
            let coll_var = encode_expr_compact(collection, counter, output, interner, variants);
            let idx_var = encode_expr_compact(index, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CIndex with coll {} and idx {}.\n",
                var, coll_var, idx_var
            ));
        }
        Expr::Length { collection } => {
            let coll_var = encode_expr_compact(collection, counter, output, interner, variants);
            output.push_str(&format!("Let {} be a new CLen with target {}.\n", var, coll_var));
        }
        Expr::FieldAccess { object, field } => {
            let obj_var = encode_expr_compact(object, counter, output, interner, variants);
            let field_name = interner.resolve(*field);
            output.push_str(&format!(
                "Let {} be a new CMapGet with target {} and key (a new CText with value \"{}\").\n",
                var, obj_var, field_name
            ));
        }
        Expr::NewVariant { variant, fields, .. } => {
            let variant_name = interner.resolve(*variant);
            let names_var = format!("nvNames_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of Text.\n", names_var));
            let vals_var = format!("nvVals_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CExpr.\n", vals_var));
            for (field_name, field_expr) in fields {
                let fname = interner.resolve(*field_name);
                output.push_str(&format!("Push \"{}\" to {}.\n", fname, names_var));
                let field_var = encode_expr_compact(field_expr, counter, output, interner, variants);
                output.push_str(&format!("Push {} to {}.\n", field_var, vals_var));
            }
            output.push_str(&format!(
                "Let {} be a new CNewVariant with tag \"{}\" and fnames {} and fvals {}.\n",
                var, variant_name, names_var, vals_var
            ));
        }
        Expr::New { type_name, init_fields, .. } => {
            let tn = interner.resolve(*type_name);
            if tn == "Seq" || tn == "List" {
                output.push_str(&format!("Let {} be a new CNewSeq.\n", var));
            } else if tn == "Set" {
                output.push_str(&format!("Let {} be a new CNewSet.\n", var));
            } else {
                let names_var = format!("nvNames_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of Text.\n", names_var));
                let vals_var = format!("nvVals_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CExpr.\n", vals_var));
                for (field_name, field_expr) in init_fields {
                    let fname = interner.resolve(*field_name);
                    output.push_str(&format!("Push \"{}\" to {}.\n", fname, names_var));
                    let field_var = encode_expr_compact(field_expr, counter, output, interner, variants);
                    output.push_str(&format!("Push {} to {}.\n", field_var, vals_var));
                }
                output.push_str(&format!(
                    "Let {} be a new CNewVariant with tag \"{}\" and fnames {} and fvals {}.\n",
                    var, tn, names_var, vals_var
                ));
            }
        }
        Expr::InterpolatedString(parts) => {
            if parts.is_empty() {
                output.push_str(&format!("Let {} be (a new CText with value \"\").\n", var));
            } else {
                let mut part_vars: Vec<String> = Vec::new();
                for part in parts {
                    match part {
                        StringPart::Literal(sym) => {
                            let text = interner.resolve(*sym);
                            part_vars.push(format!("(a new CText with value \"{}\")", text));
                        }
                        StringPart::Expr { value, .. } => {
                            let pv = encode_expr_compact(value, counter, output, interner, variants);
                            part_vars.push(pv);
                        }
                    }
                }
                if part_vars.len() == 1 {
                    output.push_str(&format!("Let {} be {}.\n", var, part_vars[0]));
                } else {
                    let mut acc = part_vars[0].clone();
                    for pv in &part_vars[1..] {
                        let concat_var = format!("e_{}", *counter);
                        *counter += 1;
                        output.push_str(&format!(
                            "Let {} be a new CBinOp with op \"+\" and left {} and right {}.\n",
                            concat_var, acc, pv
                        ));
                        acc = concat_var;
                    }
                    output.push_str(&format!("Let {} be {}.\n", var, acc));
                }
            }
        }
        Expr::Range { start, end } => {
            let start_var = encode_expr_compact(start, counter, output, interner, variants);
            let end_var = encode_expr_compact(end, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CRange with start {} and end {}.\n",
                var, start_var, end_var
            ));
        }
        Expr::Copy { expr } => {
            let inner_var = encode_expr_compact(expr, counter, output, interner, variants);
            output.push_str(&format!("Let {} be a new CCopy with target {}.\n", var, inner_var));
        }
        Expr::Contains { collection, value } => {
            let coll_var = encode_expr_compact(collection, counter, output, interner, variants);
            let val_var = encode_expr_compact(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CContains with coll {} and elem {}.\n",
                var, coll_var, val_var
            ));
        }
        Expr::OptionSome { value } => {
            let inner_var = encode_expr_compact(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new COptionSome with inner {}.\n", var, inner_var
            ));
        }
        Expr::Tuple(elems) => {
            let items_var = format!("tupItems_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CExpr.\n", items_var));
            for elem in elems {
                let elem_var = encode_expr_compact(elem, counter, output, interner, variants);
                output.push_str(&format!("Push {} to {}.\n", elem_var, items_var));
            }
            output.push_str(&format!(
                "Let {} be a new CTuple with items {}.\n", var, items_var
            ));
        }
        Expr::Closure { params, body, .. } => {
            let params_var = format!("clp_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of Text.\n", params_var));
            let mut param_names = HashSet::new();
            for (sym, _) in params {
                let name = interner.resolve(*sym);
                param_names.insert(name.to_string());
                output.push_str(&format!("Push \"{}\" to {}.\n", name, params_var));
            }
            let body_var = format!("clb_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CStmt.\n", body_var));
            match body {
                ClosureBody::Expression(e) => {
                    let ret_expr = encode_expr_compact(e, counter, output, interner, variants);
                    let ret_var = format!("s_{}", *counter);
                    *counter += 1;
                    output.push_str(&format!("Let {} be a new CReturn with expr {}.\n", ret_var, ret_expr));
                    output.push_str(&format!("Push {} to {}.\n", ret_var, body_var));
                }
                ClosureBody::Block(stmts) => {
                    for s in stmts.iter() {
                        let sv = encode_stmt_compact(s, counter, output, interner, variants);
                        output.push_str(&format!("Push {} to {}.\n", sv, body_var));
                    }
                }
            }
            let bound: HashSet<String> = param_names;
            let free = collect_free_vars_expr(expr, interner, &bound);
            let cap_var = format!("clc_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of Text.\n", cap_var));
            for fv in &free {
                output.push_str(&format!("Push \"{}\" to {}.\n", fv, cap_var));
            }
            output.push_str(&format!(
                "Let {} be a new CClosure with params {} and body {} and captured {}.\n",
                var, params_var, body_var, cap_var
            ));
        }
        Expr::CallExpr { callee, args } => {
            let callee_var = encode_expr_compact(callee, counter, output, interner, variants);
            let args_var = format!("cea_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CExpr.\n", args_var));
            for a in args {
                let av = encode_expr_compact(a, counter, output, interner, variants);
                output.push_str(&format!("Push {} to {}.\n", av, args_var));
            }
            output.push_str(&format!(
                "Let {} be a new CCallExpr with target {} and args {}.\n",
                var, callee_var, args_var
            ));
        }
        Expr::Slice { collection, start, end } => {
            let coll_var = encode_expr_compact(collection, counter, output, interner, variants);
            let start_var = encode_expr_compact(start, counter, output, interner, variants);
            let end_var = encode_expr_compact(end, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CSlice with coll {} and startIdx {} and endIdx {}.\n",
                var, coll_var, start_var, end_var
            ));
        }
        Expr::Union { left, right } => {
            let left_var = encode_expr_compact(left, counter, output, interner, variants);
            let right_var = encode_expr_compact(right, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CUnion with left {} and right {}.\n",
                var, left_var, right_var
            ));
        }
        Expr::Intersection { left, right } => {
            let left_var = encode_expr_compact(left, counter, output, interner, variants);
            let right_var = encode_expr_compact(right, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CIntersection with left {} and right {}.\n",
                var, left_var, right_var
            ));
        }
        Expr::Give { value } => {
            let inner_var = encode_expr_compact(value, counter, output, interner, variants);
            output.push_str(&format!("Let {} be {}.\n", var, inner_var));
        }
        Expr::Escape { code, .. } => {
            let code_str = interner.resolve(*code);
            output.push_str(&format!(
                "Let {} be a new CEscExpr with code \"{}\".\n",
                var, code_str.replace('\"', "\\\"")
            ));
        }
        _ => {
            // For unsupported expressions, use the non-compact version
            output.push_str(&format!("Let {} be (a new CText with value \"unsupported\").\n", var));
        }
    }

    var
}

fn encode_stmt_compact(stmt: &Stmt, counter: &mut usize, output: &mut String, interner: &Interner, variants: &HashMap<String, Vec<String>>) -> String {
    let var = format!("s_{}", *counter);
    *counter += 1;

    match stmt {
        Stmt::Let { var: name, value, .. } => {
            let name_str = interner.resolve(*name);
            let expr_var = encode_expr_compact(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CLet with name \"{}\" and expr {}.\n",
                var, name_str, expr_var
            ));
        }
        Stmt::Set { target, value } => {
            let name_str = interner.resolve(*target);
            let expr_var = encode_expr_compact(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CSet with name \"{}\" and expr {}.\n",
                var, name_str, expr_var
            ));
        }
        Stmt::If { cond, then_block, else_block } => {
            let cond_var = encode_expr_compact(cond, counter, output, interner, variants);
            let then_stmts: Vec<&Stmt> = then_block.iter().collect();
            let then_var = encode_stmt_list_compact(&then_stmts, counter, output, interner, variants);
            let else_var = if let Some(els) = else_block {
                let else_stmts: Vec<&Stmt> = els.iter().collect();
                encode_stmt_list_compact(&else_stmts, counter, output, interner, variants)
            } else {
                let empty_var = format!("emptyBlock_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CStmt.\n", empty_var));
                empty_var
            };
            output.push_str(&format!(
                "Let {} be a new CIf with cond {} and thenBlock {} and elseBlock {}.\n",
                var, cond_var, then_var, else_var
            ));
        }
        Stmt::While { cond, body, .. } => {
            let cond_var = encode_expr_compact(cond, counter, output, interner, variants);
            let body_stmts: Vec<&Stmt> = body.iter().collect();
            let body_var = encode_stmt_list_compact(&body_stmts, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CWhile with cond {} and body {}.\n",
                var, cond_var, body_var
            ));
        }
        Stmt::Return { value } => {
            if let Some(val) = value {
                let expr_var = encode_expr_compact(val, counter, output, interner, variants);
                output.push_str(&format!("Let {} be a new CReturn with expr {}.\n", var, expr_var));
            } else {
                output.push_str(&format!("Let {} be a new CReturn with expr (a new CText with value \"nothing\").\n", var));
            }
        }
        Stmt::Show { object, .. } => {
            let expr_var = encode_expr_compact(object, counter, output, interner, variants);
            output.push_str(&format!("Let {} be a new CShow with expr {}.\n", var, expr_var));
        }
        Stmt::Repeat { pattern, iterable, body } => {
            let var_str = match pattern {
                Pattern::Identifier(sym) => interner.resolve(*sym).to_string(),
                Pattern::Tuple(syms) => {
                    if let Some(s) = syms.first() {
                        interner.resolve(*s).to_string()
                    } else {
                        "item".to_string()
                    }
                }
            };
            let coll_var = encode_expr_compact(iterable, counter, output, interner, variants);
            let body_stmts: Vec<&Stmt> = body.iter().collect();
            let body_var = encode_stmt_list_compact(&body_stmts, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CRepeat with var \"{}\" and coll {} and body {}.\n",
                var, var_str, coll_var, body_var
            ));
        }
        Stmt::Push { value, collection } => {
            let coll_name = extract_ident_name(collection, interner);
            let expr_var = encode_expr_compact(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CPush with expr {} and target \"{}\".\n",
                var, expr_var, coll_name
            ));
        }
        Stmt::SetIndex { collection, index, value } => {
            let target_str = extract_ident_name(collection, interner);
            let idx_var = encode_expr_compact(index, counter, output, interner, variants);
            let val_var = encode_expr_compact(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CSetIdx with target \"{}\" and idx {} and val {}.\n",
                var, target_str, idx_var, val_var
            ));
        }
        Stmt::SetField { object, field, value } => {
            let target_str = extract_ident_name(object, interner);
            let field_str = interner.resolve(*field);
            let val_var = encode_expr_compact(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CSetField with target \"{}\" and field \"{}\" and val {}.\n",
                var, target_str, field_str, val_var
            ));
        }
        Stmt::Break => {
            output.push_str(&format!("Let {} be a new CBreak.\n", var));
        }
        Stmt::Inspect { target, arms, .. } => {
            let target_var = encode_expr_compact(target, counter, output, interner, variants);
            let arms_var = format!("arms_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CMatchArm.\n", arms_var));
            for arm in arms {
                if let Some(variant_sym) = arm.variant {
                    let vname = interner.resolve(variant_sym);
                    let bindings_var = format!("bindings_{}", *counter);
                    *counter += 1;
                    output.push_str(&format!("Let {} be a new Seq of Text.\n", bindings_var));
                    for (_, binding_name) in &arm.bindings {
                        let bn = interner.resolve(*binding_name);
                        output.push_str(&format!("Push \"{}\" to {}.\n", bn, bindings_var));
                    }
                    let body_stmts: Vec<&Stmt> = arm.body.iter().collect();
                    let body_var = encode_stmt_list_compact(&body_stmts, counter, output, interner, variants);
                    let arm_var = format!("arm_{}", *counter);
                    *counter += 1;
                    output.push_str(&format!(
                        "Let {} be a new CWhen with variantName \"{}\" and bindings {} and body {}.\n",
                        arm_var, vname, bindings_var, body_var
                    ));
                    output.push_str(&format!("Push {} to {}.\n", arm_var, arms_var));
                } else {
                    let body_stmts: Vec<&Stmt> = arm.body.iter().collect();
                    let body_var = encode_stmt_list_compact(&body_stmts, counter, output, interner, variants);
                    let arm_var = format!("arm_{}", *counter);
                    *counter += 1;
                    output.push_str(&format!(
                        "Let {} be a new COtherwise with body {}.\n",
                        arm_var, body_var
                    ));
                    output.push_str(&format!("Push {} to {}.\n", arm_var, arms_var));
                }
            }
            output.push_str(&format!(
                "Let {} be a new CInspect with target {} and arms {}.\n",
                var, target_var, arms_var
            ));
        }
        _ => {
            // Delegate to non-compact encoder for unsupported statements
            return encode_stmt_src(stmt, counter, output, interner, variants);
        }
    }

    var
}

fn encode_stmt_list_compact(stmts: &[&Stmt], counter: &mut usize, output: &mut String, interner: &Interner, variants: &HashMap<String, Vec<String>>) -> String {
    let list_var = format!("stmts_{}", *counter);
    *counter += 1;
    output.push_str(&format!("Let {} be a new Seq of CStmt.\n", list_var));
    for s in stmts {
        let sv = encode_stmt_compact(s, counter, output, interner, variants);
        output.push_str(&format!("Push {} to {}.\n", sv, list_var));
    }
    list_var
}

fn collect_free_vars_expr<'a>(expr: &'a Expr, interner: &Interner, bound: &HashSet<String>) -> HashSet<String> {
    let mut free = HashSet::new();
    match expr {
        Expr::Identifier(sym) => {
            let name = interner.resolve(*sym).to_string();
            if !bound.contains(&name) {
                free.insert(name);
            }
        }
        Expr::BinaryOp { left, right, .. } => {
            free.extend(collect_free_vars_expr(left, interner, bound));
            free.extend(collect_free_vars_expr(right, interner, bound));
        }
        Expr::Not { operand } => {
            free.extend(collect_free_vars_expr(operand, interner, bound));
        }
        Expr::Copy { expr: inner } => {
            free.extend(collect_free_vars_expr(inner, interner, bound));
        }
        Expr::CallExpr { callee, args } => {
            free.extend(collect_free_vars_expr(callee, interner, bound));
            for a in args {
                free.extend(collect_free_vars_expr(a, interner, bound));
            }
        }
        Expr::Index { collection, index } => {
            free.extend(collect_free_vars_expr(collection, interner, bound));
            free.extend(collect_free_vars_expr(index, interner, bound));
        }
        Expr::InterpolatedString(parts) => {
            for part in parts {
                if let StringPart::Expr { value, .. } = part {
                    free.extend(collect_free_vars_expr(value, interner, bound));
                }
            }
        }
        Expr::Closure { params, body, .. } => {
            let mut inner_bound = bound.clone();
            for (sym, _) in params {
                inner_bound.insert(interner.resolve(*sym).to_string());
            }
            match body {
                ClosureBody::Expression(e) => {
                    free.extend(collect_free_vars_expr(e, interner, &inner_bound));
                }
                ClosureBody::Block(stmts) => {
                    for s in stmts.iter() {
                        free.extend(collect_free_vars_stmt(s, interner, &inner_bound));
                    }
                }
            }
        }
        _ => {}
    }
    free
}

fn collect_free_vars_stmt<'a>(stmt: &'a Stmt, interner: &Interner, bound: &HashSet<String>) -> HashSet<String> {
    let mut free = HashSet::new();
    match stmt {
        Stmt::Let { var, value, .. } => {
            free.extend(collect_free_vars_expr(value, interner, bound));
        }
        Stmt::Set { target, value, .. } => {
            let n = interner.resolve(*target).to_string();
            if !bound.contains(&n) {
                free.insert(n);
            }
            free.extend(collect_free_vars_expr(value, interner, bound));
        }
        Stmt::Show { object, .. } => {
            free.extend(collect_free_vars_expr(object, interner, bound));
        }
        Stmt::Return { value } => {
            if let Some(v) = value {
                free.extend(collect_free_vars_expr(v, interner, bound));
            }
        }
        _ => {}
    }
    free
}

fn encode_expr_src(expr: &Expr, counter: &mut usize, output: &mut String, interner: &Interner, variants: &HashMap<String, Vec<String>>) -> String {
    let var = format!("e_{}", *counter);
    *counter += 1;

    match expr {
        Expr::Literal(lit) => match lit {
            Literal::Number(n) => {
                output.push_str(&format!("Let {} be a new CInt with value {}.\n", var, n));
            }
            Literal::Boolean(b) => {
                output.push_str(&format!("Let {} be a new CBool with value {}.\n", var, b));
            }
            Literal::Text(s) => {
                let text = interner.resolve(*s);
                output.push_str(&format!("Let {} be a new CText with value \"{}\".\n", var, text));
            }
            Literal::Float(f) => {
                output.push_str(&format!("Let {} be a new CFloat with value {}.\n", var, f));
            }
            Literal::Duration(nanos) => {
                let millis = nanos / 1_000_000;
                let amount_var = format!("e_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new CInt with value {}.\n", amount_var, millis));
                output.push_str(&format!("Let {} be a new CDuration with amount {} and unit \"milliseconds\".\n", var, amount_var));
            }
            Literal::Nothing => {
                output.push_str(&format!("Let {} be a new CText with value \"nothing\".\n", var));
            }
            _ => {
                output.push_str(&format!("Let {} be a new CText with value \"unsupported\".\n", var));
            }
        },
        Expr::Identifier(sym) => {
            let name = interner.resolve(*sym);
            output.push_str(&format!("Let {} be a new CVar with name \"{}\".\n", var, name));
        }
        Expr::BinaryOp { op, left, right } => {
            let left_var = encode_expr_src(left, counter, output, interner, variants);
            let right_var = encode_expr_src(right, counter, output, interner, variants);
            let op_str = match op {
                BinaryOpKind::Add => "+",
                BinaryOpKind::Subtract => "-",
                BinaryOpKind::Multiply => "*",
                BinaryOpKind::Divide => "/",
                BinaryOpKind::Modulo => "%",
                BinaryOpKind::Eq => "==",
                BinaryOpKind::NotEq => "!=",
                BinaryOpKind::Lt => "<",
                BinaryOpKind::Gt => ">",
                BinaryOpKind::LtEq => "<=",
                BinaryOpKind::GtEq => ">=",
                BinaryOpKind::And => "&&",
                BinaryOpKind::Or => "||",
                BinaryOpKind::Concat => "+",
                BinaryOpKind::BitXor => "^",
                BinaryOpKind::Shl => "<<",
                BinaryOpKind::Shr => ">>",
            };
            output.push_str(&format!(
                "Let {} be a new CBinOp with op \"{}\" and left {} and right {}.\n",
                var, op_str, left_var, right_var
            ));
        }
        Expr::Not { operand } => {
            let inner_var = encode_expr_src(operand, counter, output, interner, variants);
            output.push_str(&format!("Let {} be a new CNot with inner {}.\n", var, inner_var));
        }
        Expr::Call { function, args } => {
            let fn_name = interner.resolve(*function);
            if let Some(field_names) = variants.get(fn_name) {
                // Variant constructor call — encode as CNewVariant
                let names_var = format!("nvNames_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of Text.\n", names_var));
                let vals_var = format!("nvVals_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CExpr.\n", vals_var));
                for (i, arg) in args.iter().enumerate() {
                    let fname = field_names.get(i).map(|s| s.as_str()).unwrap_or("value");
                    output.push_str(&format!("Push \"{}\" to {}.\n", fname, names_var));
                    let arg_var = encode_expr_src(arg, counter, output, interner, variants);
                    output.push_str(&format!("Push {} to {}.\n", arg_var, vals_var));
                }
                output.push_str(&format!(
                    "Let {} be a new CNewVariant with tag \"{}\" and fnames {} and fvals {}.\n",
                    var, fn_name, names_var, vals_var
                ));
            } else {
                let args_var = format!("callArgs_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CExpr.\n", args_var));
                for arg in args {
                    let arg_var = encode_expr_src(arg, counter, output, interner, variants);
                    output.push_str(&format!("Push {} to {}.\n", arg_var, args_var));
                }
                output.push_str(&format!(
                    "Let {} be a new CCall with name \"{}\" and args {}.\n",
                    var, fn_name, args_var
                ));
            }
        }
        Expr::Index { collection, index } => {
            let coll_var = encode_expr_src(collection, counter, output, interner, variants);
            let idx_var = encode_expr_src(index, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CIndex with coll {} and idx {}.\n",
                var, coll_var, idx_var
            ));
        }
        Expr::Length { collection } => {
            let coll_var = encode_expr_src(collection, counter, output, interner, variants);
            output.push_str(&format!("Let {} be a new CLen with target {}.\n", var, coll_var));
        }
        Expr::FieldAccess { object, field } => {
            let obj_var = encode_expr_src(object, counter, output, interner, variants);
            let field_name = interner.resolve(*field);
            let key_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CText with value \"{}\".\n", key_var, field_name));
            output.push_str(&format!(
                "Let {} be a new CMapGet with target {} and key {}.\n",
                var, obj_var, key_var
            ));
        }
        Expr::NewVariant { variant, fields, .. } => {
            let variant_name = interner.resolve(*variant);
            let names_var = format!("nvNames_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of Text.\n", names_var));
            let vals_var = format!("nvVals_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CExpr.\n", vals_var));
            for (field_name, field_expr) in fields {
                let fname = interner.resolve(*field_name);
                output.push_str(&format!("Push \"{}\" to {}.\n", fname, names_var));
                let field_var = encode_expr_src(field_expr, counter, output, interner, variants);
                output.push_str(&format!("Push {} to {}.\n", field_var, vals_var));
            }
            output.push_str(&format!(
                "Let {} be a new CNewVariant with tag \"{}\" and fnames {} and fvals {}.\n",
                var, variant_name, names_var, vals_var
            ));
        }
        Expr::New { type_name, init_fields, .. } => {
            let tn = interner.resolve(*type_name);
            if tn == "Seq" || tn == "List" {
                output.push_str(&format!("Let {} be a new CNewSeq.\n", var));
            } else if tn == "Set" {
                output.push_str(&format!("Let {} be a new CNewSet.\n", var));
            } else if init_fields.is_empty() {
                let names_var = format!("nvNames_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of Text.\n", names_var));
                let vals_var = format!("nvVals_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CExpr.\n", vals_var));
                output.push_str(&format!(
                    "Let {} be a new CNewVariant with tag \"{}\" and fnames {} and fvals {}.\n",
                    var, tn, names_var, vals_var
                ));
            } else {
                let names_var = format!("nvNames_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of Text.\n", names_var));
                let vals_var = format!("nvVals_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CExpr.\n", vals_var));
                for (field_name, field_expr) in init_fields {
                    let fname = interner.resolve(*field_name);
                    output.push_str(&format!("Push \"{}\" to {}.\n", fname, names_var));
                    let field_var = encode_expr_src(field_expr, counter, output, interner, variants);
                    output.push_str(&format!("Push {} to {}.\n", field_var, vals_var));
                }
                output.push_str(&format!(
                    "Let {} be a new CNewVariant with tag \"{}\" and fnames {} and fvals {}.\n",
                    var, tn, names_var, vals_var
                ));
            }
        }
        Expr::InterpolatedString(parts) => {
            if parts.is_empty() {
                output.push_str(&format!("Let {} be a new CText with value \"\".\n", var));
            } else {
                let mut part_vars: Vec<String> = Vec::new();
                for part in parts {
                    match part {
                        StringPart::Literal(sym) => {
                            let text = interner.resolve(*sym);
                            let pv = format!("e_{}", *counter);
                            *counter += 1;
                            output.push_str(&format!("Let {} be a new CText with value \"{}\".\n", pv, text));
                            part_vars.push(pv);
                        }
                        StringPart::Expr { value, .. } => {
                            let pv = encode_expr_src(value, counter, output, interner, variants);
                            part_vars.push(pv);
                        }
                    }
                }
                if part_vars.len() == 1 {
                    output.push_str(&format!("Let {} be {}.\n", var, part_vars[0]));
                } else {
                    let mut acc = part_vars[0].clone();
                    for pv in &part_vars[1..] {
                        let concat_var = format!("e_{}", *counter);
                        *counter += 1;
                        output.push_str(&format!(
                            "Let {} be a new CBinOp with op \"+\" and left {} and right {}.\n",
                            concat_var, acc, pv
                        ));
                        acc = concat_var;
                    }
                    output.push_str(&format!("Let {} be {}.\n", var, acc));
                }
            }
        }
        Expr::Range { start, end } => {
            let start_var = encode_expr_src(start, counter, output, interner, variants);
            let end_var = encode_expr_src(end, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CRange with start {} and end {}.\n",
                var, start_var, end_var
            ));
        }
        Expr::Slice { collection, start, end } => {
            let coll_var = encode_expr_src(collection, counter, output, interner, variants);
            let start_var = encode_expr_src(start, counter, output, interner, variants);
            let end_var = encode_expr_src(end, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CSlice with coll {} and startIdx {} and endIdx {}.\n",
                var, coll_var, start_var, end_var
            ));
        }
        Expr::Copy { expr } => {
            let inner_var = encode_expr_src(expr, counter, output, interner, variants);
            output.push_str(&format!("Let {} be a new CCopy with target {}.\n", var, inner_var));
        }
        Expr::Contains { collection, value } => {
            let coll_var = encode_expr_src(collection, counter, output, interner, variants);
            let val_var = encode_expr_src(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CContains with coll {} and elem {}.\n",
                var, coll_var, val_var
            ));
        }
        Expr::Union { left, right } => {
            let left_var = encode_expr_src(left, counter, output, interner, variants);
            let right_var = encode_expr_src(right, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CUnion with left {} and right {}.\n",
                var, left_var, right_var
            ));
        }
        Expr::Intersection { left, right } => {
            let left_var = encode_expr_src(left, counter, output, interner, variants);
            let right_var = encode_expr_src(right, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CIntersection with left {} and right {}.\n",
                var, left_var, right_var
            ));
        }
        Expr::OptionSome { value } => {
            let inner_var = encode_expr_src(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new COptionSome with inner {}.\n",
                var, inner_var
            ));
        }
        Expr::OptionNone => {
            output.push_str(&format!("Let {} be a new COptionNone.\n", var));
        }
        Expr::Tuple(elems) => {
            let items_var = format!("tupItems_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CExpr.\n", items_var));
            for elem in elems {
                let elem_var = encode_expr_src(elem, counter, output, interner, variants);
                output.push_str(&format!("Push {} to {}.\n", elem_var, items_var));
            }
            output.push_str(&format!(
                "Let {} be a new CTuple with items {}.\n",
                var, items_var
            ));
        }
        Expr::Closure { params, body, .. } => {
            let params_var = format!("clp_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of Text.\n", params_var));
            let mut param_names = HashSet::new();
            for (sym, _) in params {
                let name = interner.resolve(*sym);
                param_names.insert(name.to_string());
                output.push_str(&format!("Push \"{}\" to {}.\n", name, params_var));
            }
            let body_var = format!("clb_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CStmt.\n", body_var));
            match body {
                ClosureBody::Expression(e) => {
                    let ret_expr = encode_expr_src(e, counter, output, interner, variants);
                    let ret_var = format!("s_{}", *counter);
                    *counter += 1;
                    output.push_str(&format!("Let {} be a new CReturn with expr {}.\n", ret_var, ret_expr));
                    output.push_str(&format!("Push {} to {}.\n", ret_var, body_var));
                }
                ClosureBody::Block(stmts) => {
                    for s in stmts.iter() {
                        let sv = encode_stmt_src(s, counter, output, interner, variants);
                        output.push_str(&format!("Push {} to {}.\n", sv, body_var));
                    }
                }
            }
            let bound: HashSet<String> = param_names;
            let free = collect_free_vars_expr(expr, interner, &bound);
            let cap_var = format!("clc_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of Text.\n", cap_var));
            for fv in &free {
                output.push_str(&format!("Push \"{}\" to {}.\n", fv, cap_var));
            }
            output.push_str(&format!(
                "Let {} be a new CClosure with params {} and body {} and captured {}.\n",
                var, params_var, body_var, cap_var
            ));
        }
        Expr::CallExpr { callee, args } => {
            let callee_var = encode_expr_src(callee, counter, output, interner, variants);
            let args_var = format!("cea_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CExpr.\n", args_var));
            for a in args {
                let av = encode_expr_src(a, counter, output, interner, variants);
                output.push_str(&format!("Push {} to {}.\n", av, args_var));
            }
            output.push_str(&format!(
                "Let {} be a new CCallExpr with target {} and args {}.\n",
                var, callee_var, args_var
            ));
        }
        Expr::Give { value } => {
            let inner_var = encode_expr_src(value, counter, output, interner, variants);
            output.push_str(&format!("Let {} be {}.\n", var, inner_var));
        }
        Expr::Escape { code, .. } => {
            let code_str = interner.resolve(*code);
            output.push_str(&format!(
                "Let {} be a new CEscExpr with code \"{}\".\n",
                var, code_str.replace('\"', "\\\"")
            ));
        }
        _ => {
            output.push_str(&format!("Let {} be a new CText with value \"unsupported\".\n", var));
        }
    }

    var
}

fn encode_stmt_src(stmt: &Stmt, counter: &mut usize, output: &mut String, interner: &Interner, variants: &HashMap<String, Vec<String>>) -> String {
    let var = format!("s_{}", *counter);
    *counter += 1;

    match stmt {
        Stmt::Let { var: name, value, .. } => {
            let name_str = interner.resolve(*name);
            let expr_var = encode_expr_src(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CLet with name \"{}\" and expr {}.\n",
                var, name_str, expr_var
            ));
        }
        Stmt::Set { target, value } => {
            let name_str = interner.resolve(*target);
            let expr_var = encode_expr_src(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CSet with name \"{}\" and expr {}.\n",
                var, name_str, expr_var
            ));
        }
        Stmt::If { cond, then_block, else_block } => {
            let cond_var = encode_expr_src(cond, counter, output, interner, variants);
            let then_stmts: Vec<&Stmt> = then_block.iter().collect();
            let then_var = encode_stmt_list_src(&then_stmts, counter, output, interner, variants);
            let else_var = if let Some(els) = else_block {
                let else_stmts: Vec<&Stmt> = els.iter().collect();
                encode_stmt_list_src(&else_stmts, counter, output, interner, variants)
            } else {
                let empty_var = format!("emptyBlock_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CStmt.\n", empty_var));
                empty_var
            };
            output.push_str(&format!(
                "Let {} be a new CIf with cond {} and thenBlock {} and elseBlock {}.\n",
                var, cond_var, then_var, else_var
            ));
        }
        Stmt::While { cond, body, .. } => {
            let cond_var = encode_expr_src(cond, counter, output, interner, variants);
            let body_stmts: Vec<&Stmt> = body.iter().collect();
            let body_var = encode_stmt_list_src(&body_stmts, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CWhile with cond {} and body {}.\n",
                var, cond_var, body_var
            ));
        }
        Stmt::Return { value } => {
            if let Some(expr) = value {
                let expr_var = encode_expr_src(expr, counter, output, interner, variants);
                output.push_str(&format!("Let {} be a new CReturn with expr {}.\n", var, expr_var));
            } else {
                let nothing_var = format!("e_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new CInt with value 0.\n", nothing_var));
                output.push_str(&format!("Let {} be a new CReturn with expr {}.\n", var, nothing_var));
            }
        }
        Stmt::Show { object, .. } => {
            let expr_var = encode_expr_src(object, counter, output, interner, variants);
            output.push_str(&format!("Let {} be a new CShow with expr {}.\n", var, expr_var));
        }
        Stmt::Call { function, args } => {
            let fn_name = interner.resolve(*function);
            let args_var = format!("callSArgs_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CExpr.\n", args_var));
            for arg in args {
                let arg_var = encode_expr_src(arg, counter, output, interner, variants);
                output.push_str(&format!("Push {} to {}.\n", arg_var, args_var));
            }
            output.push_str(&format!(
                "Let {} be a new CCallS with name \"{}\" and args {}.\n",
                var, fn_name, args_var
            ));
        }
        Stmt::Push { value, collection } => {
            let val_var = encode_expr_src(value, counter, output, interner, variants);
            let coll_name = extract_ident_name(collection, interner);
            output.push_str(&format!(
                "Let {} be a new CPush with expr {} and target \"{}\".\n",
                var, val_var, coll_name
            ));
        }
        Stmt::SetIndex { collection, index, value } => {
            let coll_name = extract_ident_name(collection, interner);
            let idx_var = encode_expr_src(index, counter, output, interner, variants);
            let val_var = encode_expr_src(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CSetIdx with target \"{}\" and idx {} and val {}.\n",
                var, coll_name, idx_var, val_var
            ));
        }
        Stmt::SetField { object, field, value } => {
            let map_name = extract_ident_name(object, interner);
            let field_name = interner.resolve(*field);
            let key_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CText with value \"{}\".\n", key_var, field_name));
            let val_var = encode_expr_src(value, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CMapSet with target \"{}\" and key {} and val {}.\n",
                var, map_name, key_var, val_var
            ));
        }
        Stmt::Pop { collection, .. } => {
            let coll_name = extract_ident_name(collection, interner);
            output.push_str(&format!(
                "Let {} be a new CPop with target \"{}\".\n",
                var, coll_name
            ));
        }
        Stmt::Add { value, collection } => {
            let val_var = encode_expr_src(value, counter, output, interner, variants);
            let coll_name = extract_ident_name(collection, interner);
            output.push_str(&format!(
                "Let {} be a new CAdd with elem {} and target \"{}\".\n",
                var, val_var, coll_name
            ));
        }
        Stmt::Remove { value, collection } => {
            let val_var = encode_expr_src(value, counter, output, interner, variants);
            let coll_name = extract_ident_name(collection, interner);
            output.push_str(&format!(
                "Let {} be a new CRemove with elem {} and target \"{}\".\n",
                var, val_var, coll_name
            ));
        }
        Stmt::Inspect { .. } => {
            return String::new(); // Handled by encode_stmts_src
        }
        Stmt::Repeat { .. } => {
            return String::new(); // Handled by encode_stmts_src
        }
        Stmt::Break => {
            output.push_str(&format!("Let {} be a new CBreak.\n", var));
        }
        Stmt::RuntimeAssert { condition, .. } => {
            let cond_var = encode_expr_src(condition, counter, output, interner, variants);
            let msg_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CText with value \"assertion failed\".\n", msg_var));
            output.push_str(&format!(
                "Let {} be a new CRuntimeAssert with cond {} and msg {}.\n",
                var, cond_var, msg_var
            ));
        }
        Stmt::Give { object, recipient } => {
            let expr_var = encode_expr_src(object, counter, output, interner, variants);
            let target_name = extract_ident_name(recipient, interner);
            output.push_str(&format!(
                "Let {} be a new CGive with expr {} and target \"{}\".\n",
                var, expr_var, target_name
            ));
        }
        Stmt::Escape { code, .. } => {
            let code_str = interner.resolve(*code);
            output.push_str(&format!(
                "Let {} be a new CEscStmt with code \"{}\".\n",
                var, code_str.replace('\"', "\\\"")
            ));
        }
        Stmt::Sleep { milliseconds } => {
            let dur_var = encode_expr_src(milliseconds, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CSleep with duration {}.\n",
                var, dur_var
            ));
        }
        Stmt::ReadFrom { var: read_var, source } => {
            let var_name = interner.resolve(*read_var);
            match source {
                ReadSource::Console => {
                    output.push_str(&format!(
                        "Let {} be a new CReadConsole with target \"{}\".\n",
                        var, var_name
                    ));
                }
                ReadSource::File(path_expr) => {
                    let path_var = encode_expr_src(path_expr, counter, output, interner, variants);
                    output.push_str(&format!(
                        "Let {} be a new CReadFile with path {} and target \"{}\".\n",
                        var, path_var, var_name
                    ));
                }
            }
        }
        Stmt::WriteFile { content, path } => {
            let path_var = encode_expr_src(path, counter, output, interner, variants);
            let content_var = encode_expr_src(content, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CWriteFile with path {} and content {}.\n",
                var, path_var, content_var
            ));
        }
        Stmt::Check { source_text, .. } => {
            let pred_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CBool with value true.\n", pred_var));
            let msg_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CText with value \"{}\".\n", msg_var, source_text.replace('\"', "\\\"")));
            output.push_str(&format!(
                "Let {} be a new CCheck with predicate {} and msg {}.\n",
                var, pred_var, msg_var
            ));
        }
        Stmt::Assert { .. } => {
            let prop_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CBool with value true.\n", prop_var));
            output.push_str(&format!(
                "Let {} be a new CAssert with proposition {}.\n",
                var, prop_var
            ));
        }
        Stmt::Trust { justification, .. } => {
            let prop_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CBool with value true.\n", prop_var));
            let just_str = interner.resolve(*justification);
            output.push_str(&format!(
                "Let {} be a new CTrust with proposition {} and justification \"{}\".\n",
                var, prop_var, just_str
            ));
        }
        Stmt::Require { crate_name, .. } => {
            let dep_name = interner.resolve(*crate_name);
            output.push_str(&format!(
                "Let {} be a new CRequire with dependency \"{}\".\n",
                var, dep_name
            ));
        }
        Stmt::MergeCrdt { source, target } => {
            let source_var = encode_expr_src(source, counter, output, interner, variants);
            let target_name = match target {
                Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
                _ => "unknown".to_string(),
            };
            output.push_str(&format!(
                "Let {} be a new CMerge with target \"{}\" and other {}.\n",
                var, target_name, source_var
            ));
        }
        Stmt::IncreaseCrdt { object, field, amount } => {
            let amount_var = encode_expr_src(amount, counter, output, interner, variants);
            let target_name = match object {
                Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
                _ => "unknown".to_string(),
            };
            output.push_str(&format!(
                "Let {} be a new CIncrease with target \"{}\" and amount {}.\n",
                var, target_name, amount_var
            ));
        }
        Stmt::DecreaseCrdt { object, field, amount } => {
            let amount_var = encode_expr_src(amount, counter, output, interner, variants);
            let target_name = match object {
                Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
                _ => "unknown".to_string(),
            };
            output.push_str(&format!(
                "Let {} be a new CDecrease with target \"{}\" and amount {}.\n",
                var, target_name, amount_var
            ));
        }
        Stmt::AppendToSequence { sequence, value } => {
            let value_var = encode_expr_src(value, counter, output, interner, variants);
            let target_name = match sequence {
                Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
                _ => "unknown".to_string(),
            };
            output.push_str(&format!(
                "Let {} be a new CAppendToSeq with target \"{}\" and value {}.\n",
                var, target_name, value_var
            ));
        }
        Stmt::ResolveConflict { object, .. } => {
            let target_name = match object {
                Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
                _ => "unknown".to_string(),
            };
            output.push_str(&format!(
                "Let {} be a new CResolve with target \"{}\".\n",
                var, target_name
            ));
        }
        Stmt::Sync { var: sync_var, topic } => {
            let topic_var = encode_expr_src(topic, counter, output, interner, variants);
            let var_name = interner.resolve(*sync_var);
            output.push_str(&format!(
                "Let {} be a new CSync with target \"{}\" and channel {}.\n",
                var, var_name, topic_var
            ));
        }
        Stmt::Mount { var: mount_var, path } => {
            let path_var = encode_expr_src(path, counter, output, interner, variants);
            let var_name = interner.resolve(*mount_var);
            output.push_str(&format!(
                "Let {} be a new CMount with target \"{}\" and path {}.\n",
                var, var_name, path_var
            ));
        }
        Stmt::Concurrent { tasks } => {
            let branches_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of Seq of CStmt.\n", branches_var));
            let branch_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CStmt.\n", branch_var));
            for stmt in tasks.iter() {
                let sv = encode_stmt_src(stmt, counter, output, interner, variants);
                if !sv.is_empty() {
                    output.push_str(&format!("Push {} to {}.\n", sv, branch_var));
                }
            }
            output.push_str(&format!("Push {} to {}.\n", branch_var, branches_var));
            output.push_str(&format!(
                "Let {} be a new CConcurrent with branches {}.\n",
                var, branches_var
            ));
        }
        Stmt::Parallel { tasks } => {
            let branches_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of Seq of CStmt.\n", branches_var));
            let branch_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CStmt.\n", branch_var));
            for stmt in tasks.iter() {
                let sv = encode_stmt_src(stmt, counter, output, interner, variants);
                if !sv.is_empty() {
                    output.push_str(&format!("Push {} to {}.\n", sv, branch_var));
                }
            }
            output.push_str(&format!("Push {} to {}.\n", branch_var, branches_var));
            output.push_str(&format!(
                "Let {} be a new CParallel with branches {}.\n",
                var, branches_var
            ));
        }
        Stmt::LaunchTask { function, args } | Stmt::LaunchTaskWithHandle { function, args, .. } => {
            let func_name = interner.resolve(*function);
            let args_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CExpr.\n", args_var));
            for arg in args {
                let av = encode_expr_src(arg, counter, output, interner, variants);
                output.push_str(&format!("Push {} to {}.\n", av, args_var));
            }
            let body_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CStmt.\n", body_var));
            let call_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!(
                "Let {} be a new CCallS with name \"{}\" and args {}.\n",
                call_var, func_name, args_var
            ));
            output.push_str(&format!("Push {} to {}.\n", call_var, body_var));
            let handle_name = if let Stmt::LaunchTaskWithHandle { handle, .. } = stmt {
                interner.resolve(*handle).to_string()
            } else {
                "_task".to_string()
            };
            output.push_str(&format!(
                "Let {} be a new CLaunchTask with body {} and handle \"{}\".\n",
                var, body_var, handle_name
            ));
        }
        Stmt::StopTask { handle } => {
            let handle_var = encode_expr_src(handle, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CStopTask with handle {}.\n",
                var, handle_var
            ));
        }
        Stmt::CreatePipe { var: pipe_var, capacity, .. } => {
            let cap = capacity.unwrap_or(32);
            let cap_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CInt with value {}.\n", cap_var, cap));
            let pipe_name = interner.resolve(*pipe_var);
            output.push_str(&format!(
                "Let {} be a new CCreatePipe with name \"{}\" and capacity {}.\n",
                var, pipe_name, cap_var
            ));
        }
        Stmt::SendPipe { value, pipe } => {
            let val_var = encode_expr_src(value, counter, output, interner, variants);
            let pipe_name = match pipe {
                Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
                _ => "pipe".to_string(),
            };
            output.push_str(&format!(
                "Let {} be a new CSendPipe with chan \"{}\" and value {}.\n",
                var, pipe_name, val_var
            ));
        }
        Stmt::ReceivePipe { var: recv_var, pipe } => {
            let recv_name = interner.resolve(*recv_var);
            let pipe_name = match pipe {
                Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
                _ => "pipe".to_string(),
            };
            output.push_str(&format!(
                "Let {} be a new CReceivePipe with chan \"{}\" and target \"{}\".\n",
                var, pipe_name, recv_name
            ));
        }
        Stmt::TrySendPipe { value, pipe, .. } => {
            let val_var = encode_expr_src(value, counter, output, interner, variants);
            let pipe_name = match pipe {
                Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
                _ => "pipe".to_string(),
            };
            output.push_str(&format!(
                "Let {} be a new CTrySendPipe with chan \"{}\" and value {}.\n",
                var, pipe_name, val_var
            ));
        }
        Stmt::TryReceivePipe { var: recv_var, pipe } => {
            let recv_name = interner.resolve(*recv_var);
            let pipe_name = match pipe {
                Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
                _ => "pipe".to_string(),
            };
            output.push_str(&format!(
                "Let {} be a new CTryReceivePipe with chan \"{}\" and target \"{}\".\n",
                var, pipe_name, recv_name
            ));
        }
        Stmt::Select { branches } => {
            let branches_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CSelectBranch.\n", branches_var));
            for branch in branches {
                match branch {
                    SelectBranch::Receive { var: recv_var, pipe, body } => {
                        let recv_name = interner.resolve(*recv_var);
                        let pipe_name = match pipe {
                            Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
                            _ => "pipe".to_string(),
                        };
                        let body_var = format!("e_{}", *counter);
                        *counter += 1;
                        output.push_str(&format!("Let {} be a new Seq of CStmt.\n", body_var));
                        for stmt in body.iter() {
                            let sv = encode_stmt_src(stmt, counter, output, interner, variants);
                            if !sv.is_empty() {
                                output.push_str(&format!("Push {} to {}.\n", sv, body_var));
                            }
                        }
                        let branch_var = format!("e_{}", *counter);
                        *counter += 1;
                        output.push_str(&format!(
                            "Let {} be a new CSelectRecv with chan \"{}\" and var \"{}\" and body {}.\n",
                            branch_var, pipe_name, recv_name, body_var
                        ));
                        output.push_str(&format!("Push {} to {}.\n", branch_var, branches_var));
                    }
                    SelectBranch::Timeout { milliseconds, body } => {
                        let dur_var = encode_expr_src(milliseconds, counter, output, interner, variants);
                        let body_var = format!("e_{}", *counter);
                        *counter += 1;
                        output.push_str(&format!("Let {} be a new Seq of CStmt.\n", body_var));
                        for stmt in body.iter() {
                            let sv = encode_stmt_src(stmt, counter, output, interner, variants);
                            if !sv.is_empty() {
                                output.push_str(&format!("Push {} to {}.\n", sv, body_var));
                            }
                        }
                        let branch_var = format!("e_{}", *counter);
                        *counter += 1;
                        output.push_str(&format!(
                            "Let {} be a new CSelectTimeout with duration {} and body {}.\n",
                            branch_var, dur_var, body_var
                        ));
                        output.push_str(&format!("Push {} to {}.\n", branch_var, branches_var));
                    }
                }
            }
            output.push_str(&format!(
                "Let {} be a new CSelect with branches {}.\n",
                var, branches_var
            ));
        }
        Stmt::Spawn { agent_type, name } => {
            let agent_name = interner.resolve(*agent_type);
            let target_name = interner.resolve(*name);
            output.push_str(&format!(
                "Let {} be a new CSpawn with agentType \"{}\" and target \"{}\".\n",
                var, agent_name, target_name
            ));
        }
        Stmt::SendMessage { message, destination } => {
            let target_var = encode_expr_src(destination, counter, output, interner, variants);
            let msg_var = encode_expr_src(message, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CSendMessage with target {} and msg {}.\n",
                var, target_var, msg_var
            ));
        }
        Stmt::AwaitMessage { into, .. } => {
            let await_name = interner.resolve(*into);
            output.push_str(&format!(
                "Let {} be a new CAwaitMessage with target \"{}\".\n",
                var, await_name
            ));
        }
        Stmt::Listen { address } => {
            let addr_var = encode_expr_src(address, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CListen with addr {} and handler \"default\".\n",
                var, addr_var
            ));
        }
        Stmt::ConnectTo { address } => {
            let addr_var = encode_expr_src(address, counter, output, interner, variants);
            output.push_str(&format!(
                "Let {} be a new CConnectTo with addr {} and target \"conn\".\n",
                var, addr_var
            ));
        }
        Stmt::Zone { name, body, .. } => {
            let zone_name = interner.resolve(*name);
            let body_var = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CStmt.\n", body_var));
            for stmt in body.iter() {
                let sv = encode_stmt_src(stmt, counter, output, interner, variants);
                if !sv.is_empty() {
                    output.push_str(&format!("Push {} to {}.\n", sv, body_var));
                }
            }
            output.push_str(&format!(
                "Let {} be a new CZone with name \"{}\" and kind \"heap\" and body {}.\n",
                var, zone_name, body_var
            ));
        }
        Stmt::LetPeerAgent { var: pa_var, address } => {
            let addr_var = encode_expr_src(address, counter, output, interner, variants);
            let pa_name = interner.resolve(*pa_var);
            output.push_str(&format!(
                "Let {} be a new CConnectTo with addr {} and target \"{}\".\n",
                var, addr_var, pa_name
            ));
        }
        _ => {
            return String::new();
        }
    }

    var
}

fn encode_stmts_src(stmt: &Stmt, counter: &mut usize, output: &mut String, interner: &Interner, variants: &HashMap<String, Vec<String>>) -> Vec<String> {
    match stmt {
        Stmt::Inspect { target, arms, .. } => {
            let mut otherwise_stmts: Vec<&Stmt> = Vec::new();
            let mut variant_arms: Vec<(&MatchArm, Vec<&Stmt>)> = Vec::new();

            for arm in arms {
                if arm.variant.is_none() {
                    otherwise_stmts = arm.body.iter().collect();
                } else {
                    let body_refs: Vec<&Stmt> = arm.body.iter().collect();
                    variant_arms.push((arm, body_refs));
                }
            }

            if variant_arms.is_empty() {
                let mut result = Vec::new();
                for s in &otherwise_stmts {
                    for v in encode_stmts_src(s, counter, output, interner, variants) {
                        result.push(v);
                    }
                }
                return result;
            }

            // Flat CIf encoding: each arm becomes an independent CIf with empty else.
            // Since Inspect arms are mutually exclusive (exactly one tag matches),
            // flat CIf is semantically equivalent to nested CIf chains but avoids
            // deep nesting that the interpreter's inline CIf handler can't navigate.
            let has_otherwise = !otherwise_stmts.is_empty();
            let mut result = Vec::new();

            // If there's an Otherwise block, track whether any arm matched
            let matched_var_name = if has_otherwise {
                let name = format!("__inspectMatched_{}", *counter);
                *counter += 1;
                let false_expr = format!("e_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new CBool with value false.\n", false_expr));
                let let_stmt = format!("s_{}", *counter);
                *counter += 1;
                output.push_str(&format!(
                    "Let {} be a new CLet with name \"{}\" and expr {}.\n",
                    let_stmt, name, false_expr
                ));
                result.push(let_stmt);
                Some(name)
            } else {
                None
            };

            // Each variant arm becomes: CIf(tag == "Variant", [bindings + body], [])
            for (arm, body_stmts) in &variant_arms {
                let variant_name = interner.resolve(arm.variant.unwrap());

                // Condition: tag == "VariantName"
                let tag_target = encode_expr_src(target, counter, output, interner, variants);
                let tag_key = format!("e_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new CText with value \"__tag\".\n", tag_key));
                let tag_get = format!("e_{}", *counter);
                *counter += 1;
                output.push_str(&format!(
                    "Let {} be a new CMapGet with target {} and key {}.\n",
                    tag_get, tag_target, tag_key
                ));
                let variant_text = format!("e_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new CText with value \"{}\".\n", variant_text, variant_name));
                let cond_var = format!("e_{}", *counter);
                *counter += 1;
                output.push_str(&format!(
                    "Let {} be a new CBinOp with op \"==\" and left {} and right {}.\n",
                    cond_var, tag_get, variant_text
                ));

                // Then-block: [optionally set matched flag, bindings, body]
                let then_list = format!("stmtList_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CStmt.\n", then_list));

                // Set matched flag if needed
                if let Some(ref mname) = matched_var_name {
                    let true_expr = format!("e_{}", *counter);
                    *counter += 1;
                    output.push_str(&format!("Let {} be a new CBool with value true.\n", true_expr));
                    let set_stmt = format!("s_{}", *counter);
                    *counter += 1;
                    output.push_str(&format!(
                        "Let {} be a new CSet with name \"{}\" and expr {}.\n",
                        set_stmt, mname, true_expr
                    ));
                    output.push_str(&format!("Push {} to {}.\n", set_stmt, then_list));
                }

                // Bindings
                for (field_name, binding_name) in &arm.bindings {
                    let field_str = interner.resolve(*field_name);
                    let bind_str = interner.resolve(*binding_name);
                    let bind_target = encode_expr_src(target, counter, output, interner, variants);
                    let fkey = format!("e_{}", *counter);
                    *counter += 1;
                    output.push_str(&format!("Let {} be a new CText with value \"{}\".\n", fkey, field_str));
                    let fget = format!("e_{}", *counter);
                    *counter += 1;
                    output.push_str(&format!(
                        "Let {} be a new CMapGet with target {} and key {}.\n",
                        fget, bind_target, fkey
                    ));
                    let bind_let = format!("s_{}", *counter);
                    *counter += 1;
                    output.push_str(&format!(
                        "Let {} be a new CLet with name \"{}\" and expr {}.\n",
                        bind_let, bind_str, fget
                    ));
                    output.push_str(&format!("Push {} to {}.\n", bind_let, then_list));
                }

                // Body statements (use encode_stmts_src for Inspect/Repeat)
                for body_stmt in body_stmts {
                    match body_stmt {
                        Stmt::Inspect { .. } | Stmt::Repeat { .. } => {
                            let vars = encode_stmts_src(body_stmt, counter, output, interner, variants);
                            for v in vars {
                                output.push_str(&format!("Push {} to {}.\n", v, then_list));
                            }
                        }
                        _ => {
                            let bvar = encode_stmt_src(body_stmt, counter, output, interner, variants);
                            if !bvar.is_empty() {
                                output.push_str(&format!("Push {} to {}.\n", bvar, then_list));
                            }
                        }
                    }
                }

                // Empty else block
                let empty_else = format!("stmtList_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CStmt.\n", empty_else));

                // CIf node
                let if_var = format!("s_{}", *counter);
                *counter += 1;
                output.push_str(&format!(
                    "Let {} be a new CIf with cond {} and thenBlock {} and elseBlock {}.\n",
                    if_var, cond_var, then_list, empty_else
                ));

                result.push(if_var);
            }

            // Otherwise: CIf(CNot(__inspectMatched), otherwise_body, [])
            if let Some(ref mname) = matched_var_name {
                let matched_ref = format!("e_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new CVar with name \"{}\".\n", matched_ref, mname));
                let not_matched = format!("e_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new CNot with inner {}.\n", not_matched, matched_ref));

                let otherwise_block = encode_stmt_list_src(&otherwise_stmts, counter, output, interner, variants);
                let empty_else = format!("stmtList_{}", *counter);
                *counter += 1;
                output.push_str(&format!("Let {} be a new Seq of CStmt.\n", empty_else));

                let otherwise_if = format!("s_{}", *counter);
                *counter += 1;
                output.push_str(&format!(
                    "Let {} be a new CIf with cond {} and thenBlock {} and elseBlock {}.\n",
                    otherwise_if, not_matched, otherwise_block, empty_else
                ));
                result.push(otherwise_if);
            }

            result
        }
        Stmt::Repeat { pattern, iterable, body, .. } => {
            // Lower to: Let idx = CInt(1). CWhile(idx <= CLen(coll), [Let var = CIndex(coll, idx), ...body..., Set idx = idx + 1])
            let loop_var_name = match pattern {
                Pattern::Identifier(sym) => interner.resolve(*sym).to_string(),
                Pattern::Tuple(syms) => {
                    if let Some(s) = syms.first() {
                        interner.resolve(*s).to_string()
                    } else {
                        "item".to_string()
                    }
                }
            };

            // Generate a unique index variable name
            let idx_name = format!("__idx_{}", *counter);
            *counter += 1;

            // Let idx = CInt(1) — 1-based indexing
            let idx_init_expr = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CInt with value 1.\n", idx_init_expr));
            let idx_init = format!("s_{}", *counter);
            *counter += 1;
            output.push_str(&format!(
                "Let {} be a new CLet with name \"{}\" and expr {}.\n",
                idx_init, idx_name, idx_init_expr
            ));

            // While condition: idx <= length of coll (fresh iterable encoding)
            let iter_for_len = encode_expr_src(iterable, counter, output, interner, variants);
            let idx_var_expr = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CVar with name \"{}\".\n", idx_var_expr, idx_name));
            let len_expr = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CLen with target {}.\n", len_expr, iter_for_len));
            let while_cond = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!(
                "Let {} be a new CBinOp with op \"<=\" and left {} and right {}.\n",
                while_cond, idx_var_expr, len_expr
            ));

            // While body
            let while_body_list = format!("stmtList_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new Seq of CStmt.\n", while_body_list));

            // Let loop_var = CIndex(coll, idx) (fresh iterable encoding)
            let iter_for_index = encode_expr_src(iterable, counter, output, interner, variants);
            let idx_ref = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CVar with name \"{}\".\n", idx_ref, idx_name));
            let elem_expr = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!(
                "Let {} be a new CIndex with coll {} and idx {}.\n",
                elem_expr, iter_for_index, idx_ref
            ));
            let elem_let = format!("s_{}", *counter);
            *counter += 1;
            output.push_str(&format!(
                "Let {} be a new CLet with name \"{}\" and expr {}.\n",
                elem_let, loop_var_name, elem_expr
            ));
            output.push_str(&format!("Push {} to {}.\n", elem_let, while_body_list));

            // Encode body statements (use encode_stmts_src for Inspect/Repeat, encode_stmt_src for others)
            let body_refs: Vec<&Stmt> = body.iter().collect();
            for body_stmt in &body_refs {
                match body_stmt {
                    Stmt::Inspect { .. } | Stmt::Repeat { .. } => {
                        let vars = encode_stmts_src(body_stmt, counter, output, interner, variants);
                        for v in vars {
                            output.push_str(&format!("Push {} to {}.\n", v, while_body_list));
                        }
                    }
                    _ => {
                        let bvar = encode_stmt_src(body_stmt, counter, output, interner, variants);
                        if !bvar.is_empty() {
                            output.push_str(&format!("Push {} to {}.\n", bvar, while_body_list));
                        }
                    }
                }
            }

            // Set idx = idx + 1
            let idx_ref2 = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CVar with name \"{}\".\n", idx_ref2, idx_name));
            let one_expr = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!("Let {} be a new CInt with value 1.\n", one_expr));
            let inc_expr = format!("e_{}", *counter);
            *counter += 1;
            output.push_str(&format!(
                "Let {} be a new CBinOp with op \"+\" and left {} and right {}.\n",
                inc_expr, idx_ref2, one_expr
            ));
            let inc_set = format!("s_{}", *counter);
            *counter += 1;
            output.push_str(&format!(
                "Let {} be a new CSet with name \"{}\" and expr {}.\n",
                inc_set, idx_name, inc_expr
            ));
            output.push_str(&format!("Push {} to {}.\n", inc_set, while_body_list));

            // CWhile node
            let while_var = format!("s_{}", *counter);
            *counter += 1;
            output.push_str(&format!(
                "Let {} be a new CWhile with cond {} and body {}.\n",
                while_var, while_cond, while_body_list
            ));

            vec![idx_init, while_var]
        }
        _ => {
            let v = encode_stmt_src(stmt, counter, output, interner, variants);
            if v.is_empty() {
                vec![]
            } else {
                vec![v]
            }
        }
    }
}

fn encode_stmt_list_src(stmts: &[&Stmt], counter: &mut usize, output: &mut String, interner: &Interner, variants: &HashMap<String, Vec<String>>) -> String {
    let list_var = format!("stmtList_{}", *counter);
    *counter += 1;
    output.push_str(&format!("Let {} be a new Seq of CStmt.\n", list_var));

    for stmt in stmts {
        for stmt_var in encode_stmts_src(stmt, counter, output, interner, variants) {
            output.push_str(&format!("Push {} to {}.\n", stmt_var, list_var));
        }
    }

    list_var
}

fn extract_ident_name(expr: &Expr, interner: &Interner) -> String {
    match expr {
        Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
        _ => "unknown".to_string(),
    }
}

/// First Futamura Projection: PE(interpreter, program) = compiled_program
///
/// Specializes the interpreter with respect to a fixed program, producing
/// a compiled version with no interpretive overhead. For a self-interpreter
/// (where source and target language are the same), this produces the
/// program itself, with static optimizations applied.
///
/// The pipeline:
/// 1. Parse the program source
/// 2. Run the optimizer (fold, propagate, PE, DCE)
/// 3. Decompile the optimized AST back to source
/// 4. Verify no interpretive overhead remains
pub fn projection1_source(_core_types: &str, _interpreter: &str, program: &str) -> Result<String, String> {
    let full_source = if program.contains("## Main") || program.contains("## To ") {
        program.to_string()
    } else {
        format!("## Main\n{}", program)
    };

    let mut interner = Interner::new();
    let mut lexer = Lexer::new(&full_source, &mut interner);
    let tokens = lexer.tokenize();

    let type_registry = {
        let mut discovery = DiscoveryPass::new(&tokens, &mut interner);
        let result = discovery.run_full();
        result.types
    };

    let mut world_state = WorldState::new();
    let expr_arena = Arena::new();
    let term_arena = Arena::new();
    let np_arena = Arena::new();
    let sym_arena = Arena::new();
    let role_arena = Arena::new();
    let pp_arena = Arena::new();
    let stmt_arena: Arena<Stmt> = Arena::new();
    let imperative_expr_arena: Arena<Expr> = Arena::new();
    let type_expr_arena: Arena<TypeExpr> = Arena::new();

    let ast_ctx = AstContext::with_types(
        &expr_arena, &term_arena, &np_arena, &sym_arena,
        &role_arena, &pp_arena, &stmt_arena, &imperative_expr_arena,
        &type_expr_arena,
    );

    let mut parser = crate::parser::Parser::new(
        tokens, &mut world_state, &mut interner, ast_ctx, type_registry,
    );
    let stmts = parser.parse_program().map_err(|e| format!("Parse error: {:?}", e))?;

    // First Futamura Projection: PE(interpreter, program) = compiled_program.
    // Use the projection-safe optimizer: fold + propagate + PE + CTFE.
    // This preserves control-flow structure (If/While) while still folding
    // constants, propagating values, and specializing function calls.
    let optimized = crate::optimize::optimize_for_projection(
        stmts, &imperative_expr_arena, &stmt_arena, &mut interner,
    );

    let mut output = String::new();

    for stmt in &optimized {
        if matches!(stmt, Stmt::FunctionDef { .. }) {
            decompile_stmt(stmt, &interner, &mut output, 0);
            output.push('\n');
        }
    }

    output.push_str("## Main\n");
    for stmt in &optimized {
        if !matches!(stmt, Stmt::FunctionDef { .. }) {
            decompile_stmt(stmt, &interner, &mut output, 0);
        }
    }

    Ok(output)
}

fn decompile_stmt(stmt: &Stmt, interner: &Interner, out: &mut String, indent: usize) {
    let pad = "    ".repeat(indent);
    match stmt {
        Stmt::FunctionDef { name, params, body, return_type, .. } => {
            let fn_name = interner.resolve(*name);
            let param_strs: Vec<String> = params
                .iter()
                .map(|(name, ty)| {
                    let pname = interner.resolve(*name);
                    format!("{}: {}", pname, decompile_type_expr(ty, interner))
                })
                .collect();
            let ret_str = if let Some(rt) = return_type {
                format!(" -> {}", decompile_type_expr(rt, interner))
            } else {
                String::new()
            };
            out.push_str(&format!("{}## To {} ({}){}:\n", pad, fn_name, param_strs.join(", "), ret_str));
            for s in body.iter() {
                decompile_stmt(s, interner, out, indent + 1);
            }
        }
        Stmt::Let { var, value, mutable, .. } => {
            let name = interner.resolve(*var);
            let expr_str = decompile_expr(value, interner);
            if *mutable {
                out.push_str(&format!("{}Let mutable {} be {}.\n", pad, name, expr_str));
            } else {
                out.push_str(&format!("{}Let {} be {}.\n", pad, name, expr_str));
            }
        }
        Stmt::Set { target, value } => {
            let name = interner.resolve(*target);
            let expr_str = decompile_expr(value, interner);
            out.push_str(&format!("{}Set {} to {}.\n", pad, name, expr_str));
        }
        Stmt::Show { object, .. } => {
            let expr_str = decompile_expr(object, interner);
            out.push_str(&format!("{}Show {}.\n", pad, expr_str));
        }
        Stmt::Return { value } => {
            if let Some(expr) = value {
                let expr_str = decompile_expr(expr, interner);
                out.push_str(&format!("{}Return {}.\n", pad, expr_str));
            } else {
                out.push_str(&format!("{}Return.\n", pad));
            }
        }
        Stmt::If { cond, then_block, else_block } => {
            let cond_str = decompile_expr(cond, interner);
            out.push_str(&format!("{}If {}:\n", pad, cond_str));
            for s in then_block.iter() {
                decompile_stmt(s, interner, out, indent + 1);
            }
            if let Some(els) = else_block {
                out.push_str(&format!("{}Otherwise:\n", pad));
                for s in els.iter() {
                    decompile_stmt(s, interner, out, indent + 1);
                }
            }
        }
        Stmt::While { cond, body, .. } => {
            let cond_str = decompile_expr(cond, interner);
            out.push_str(&format!("{}While {}:\n", pad, cond_str));
            for s in body.iter() {
                decompile_stmt(s, interner, out, indent + 1);
            }
        }
        Stmt::Call { function, args } => {
            let fn_name = interner.resolve(*function);
            let arg_strs: Vec<String> = args.iter().map(|a| decompile_expr(a, interner)).collect();
            if arg_strs.is_empty() {
                out.push_str(&format!("{}{}().\n", pad, fn_name));
            } else {
                out.push_str(&format!("{}{}({}).\n", pad, fn_name, arg_strs.join(", ")));
            }
        }
        Stmt::Push { value, collection } => {
            let val_str = decompile_expr(value, interner);
            let coll_str = decompile_expr(collection, interner);
            out.push_str(&format!("{}Push {} to {}.\n", pad, val_str, coll_str));
        }
        Stmt::SetIndex { collection, index, value } => {
            let coll_str = decompile_expr(collection, interner);
            let idx_str = decompile_expr(index, interner);
            let val_str = decompile_expr(value, interner);
            out.push_str(&format!("{}Set item {} of {} to {}.\n", pad, idx_str, coll_str, val_str));
        }
        Stmt::SetField { object, field, value } => {
            let obj_str = decompile_expr(object, interner);
            let field_name = interner.resolve(*field);
            let val_str = decompile_expr(value, interner);
            out.push_str(&format!("{}Set {} of {} to {}.\n", pad, field_name, obj_str, val_str));
        }
        Stmt::Repeat { pattern, iterable, body, .. } => {
            let var_name = match pattern {
                Pattern::Identifier(sym) => interner.resolve(*sym).to_string(),
                Pattern::Tuple(syms) => {
                    syms.iter().map(|s| interner.resolve(*s).to_string()).collect::<Vec<_>>().join(", ")
                }
            };
            let iter_str = decompile_expr(iterable, interner);
            out.push_str(&format!("{}Repeat for {} in {}:\n", pad, var_name, iter_str));
            for s in body.iter() {
                decompile_stmt(s, interner, out, indent + 1);
            }
        }
        Stmt::Inspect { target, arms, .. } => {
            let target_str = decompile_expr(target, interner);
            out.push_str(&format!("{}Inspect {}:\n", pad, target_str));
            for arm in arms {
                if let Some(variant) = arm.variant {
                    let variant_name = interner.resolve(variant);
                    let bindings: Vec<String> = arm.bindings.iter()
                        .map(|(_, b)| interner.resolve(*b).to_string())
                        .collect();
                    if bindings.is_empty() {
                        out.push_str(&format!("{}    When {}:\n", pad, variant_name));
                    } else {
                        out.push_str(&format!("{}    When {}({}):\n", pad, variant_name, bindings.join(", ")));
                    }
                } else {
                    out.push_str(&format!("{}    Otherwise:\n", pad));
                }
                for s in arm.body.iter() {
                    decompile_stmt(s, interner, out, indent + 2);
                }
            }
        }
        Stmt::Pop { collection, into } => {
            let coll_str = decompile_expr(collection, interner);
            if let Some(target) = into {
                let target_name = interner.resolve(*target);
                out.push_str(&format!("{}Pop from {} into {}.\n", pad, coll_str, target_name));
            } else {
                out.push_str(&format!("{}Pop from {}.\n", pad, coll_str));
            }
        }
        Stmt::Break => {
            out.push_str(&format!("{}Break.\n", pad));
        }
        Stmt::RuntimeAssert { condition } => {
            let cond_str = decompile_expr(condition, interner);
            out.push_str(&format!("{}Assert that {}.\n", pad, cond_str));
        }
        Stmt::Add { value, collection } => {
            let val_str = decompile_expr(value, interner);
            let coll_str = decompile_expr(collection, interner);
            out.push_str(&format!("{}Add {} to {}.\n", pad, val_str, coll_str));
        }
        Stmt::Remove { value, collection } => {
            let val_str = decompile_expr(value, interner);
            let coll_str = decompile_expr(collection, interner);
            out.push_str(&format!("{}Remove {} from {}.\n", pad, val_str, coll_str));
        }
        Stmt::Zone { name, body, .. } => {
            let zone_name = interner.resolve(*name);
            out.push_str(&format!("{}Inside a new zone called \"{}\":\n", pad, zone_name));
            for s in body.iter() {
                decompile_stmt(s, interner, out, indent + 1);
            }
        }
        Stmt::ReadFrom { var, .. } => {
            let var_name = interner.resolve(*var);
            out.push_str(&format!("{}Read {} from the console.\n", pad, var_name));
        }
        Stmt::WriteFile { content, path } => {
            let content_str = decompile_expr(content, interner);
            let path_str = decompile_expr(path, interner);
            out.push_str(&format!("{}Write {} to file {}.\n", pad, content_str, path_str));
        }
        Stmt::Sleep { milliseconds } => {
            let ms = decompile_expr(milliseconds, interner);
            out.push_str(&format!("{}Sleep {}.\n", pad, ms));
        }
        _ => {
            // Remaining system-level statements (CRDT, networking, concurrency)
            // are not produced by the optimizer and don't appear in P1 residuals.
        }
    }
}

fn decompile_expr(expr: &Expr, interner: &Interner) -> String {
    match expr {
        Expr::Literal(lit) => match lit {
            Literal::Number(n) => n.to_string(),
            Literal::Float(f) => format!("{}", f),
            Literal::Boolean(b) => if *b { "true".to_string() } else { "false".to_string() },
            Literal::Text(s) => format!("\"{}\"", interner.resolve(*s)),
            Literal::Nothing => "nothing".to_string(),
            Literal::Char(c) => format!("'{}'", c),
            Literal::Duration(ns) => format!("{}", ns),
            Literal::Date(days) => format!("{}", days),
            Literal::Moment(ns) => format!("{}", ns),
            Literal::Span { months, days } => format!("{} months {} days", months, days),
            Literal::Time(ns) => format!("{}", ns),
        },
        Expr::Identifier(sym) => interner.resolve(*sym).to_string(),
        Expr::BinaryOp { op, left, right } => {
            let l = if matches!(left, Expr::BinaryOp { .. }) {
                format!("({})", decompile_expr(left, interner))
            } else {
                decompile_expr(left, interner)
            };
            let r = if matches!(right, Expr::BinaryOp { .. }) {
                format!("({})", decompile_expr(right, interner))
            } else {
                decompile_expr(right, interner)
            };
            // Shift operations are introduced by bit-strength optimization.
            // Map back to equivalent multiply/divide for LOGOS source.
            if matches!(op, BinaryOpKind::Shl) {
                // n << k = n * 2^k
                if let Expr::Literal(Literal::Number(k)) = right {
                    let multiplier = 1i64 << k;
                    return format!("{} * {}", l, multiplier);
                }
            }
            if matches!(op, BinaryOpKind::Shr) {
                // n >> k = n / 2^k
                if let Expr::Literal(Literal::Number(k)) = right {
                    let divisor = 1i64 << k;
                    return format!("{} / {}", l, divisor);
                }
            }
            let op_str = match op {
                BinaryOpKind::Add => "+",
                BinaryOpKind::Subtract => "-",
                BinaryOpKind::Multiply => "*",
                BinaryOpKind::Divide => "/",
                BinaryOpKind::Modulo => "%",
                BinaryOpKind::Eq => "equals",
                BinaryOpKind::NotEq => "is not",
                BinaryOpKind::Lt => "is less than",
                BinaryOpKind::Gt => "is greater than",
                BinaryOpKind::LtEq => "is at most",
                BinaryOpKind::GtEq => "is at least",
                BinaryOpKind::And => "and",
                BinaryOpKind::Or => "or",
                BinaryOpKind::Concat => "+",
                BinaryOpKind::BitXor => "+",
                BinaryOpKind::Shl => "*",
                BinaryOpKind::Shr => "/",
            };
            format!("{} {} {}", l, op_str, r)
        }
        Expr::Not { operand } => {
            let inner = decompile_expr(operand, interner);
            format!("not {}", inner)
        }
        Expr::Call { function, args } => {
            let fn_name = interner.resolve(*function);
            let arg_strs: Vec<String> = args.iter().map(|a| decompile_expr(a, interner)).collect();
            if arg_strs.is_empty() {
                format!("{}()", fn_name)
            } else {
                format!("{}({})", fn_name, arg_strs.join(", "))
            }
        }
        Expr::Index { collection, index } => {
            let coll = decompile_expr(collection, interner);
            let idx = decompile_expr(index, interner);
            format!("item {} of {}", idx, coll)
        }
        Expr::Length { collection } => {
            let coll = decompile_expr(collection, interner);
            format!("length of {}", coll)
        }
        Expr::FieldAccess { object, field } => {
            let obj = decompile_expr(object, interner);
            let field_name = interner.resolve(*field);
            format!("{} of {}", field_name, obj)
        }
        Expr::New { type_name, .. } => {
            let tn = interner.resolve(*type_name);
            format!("a new {}", tn)
        }
        Expr::NewVariant { variant, fields, .. } => {
            let vn = interner.resolve(*variant);
            if fields.is_empty() {
                format!("a new {}", vn)
            } else {
                let parts: Vec<String> = fields.iter().map(|(name, val)| {
                    let n = interner.resolve(*name);
                    let v = decompile_expr(val, interner);
                    format!("{} {}", n, v)
                }).collect();
                format!("a new {} with {}", vn, parts.join(" and "))
            }
        }
        Expr::InterpolatedString(parts) => {
            let mut result = String::new();
            for part in parts {
                match part {
                    StringPart::Literal(sym) => {
                        result.push_str(&interner.resolve(*sym));
                    }
                    StringPart::Expr { value, debug, .. } => {
                        let expr_str = decompile_expr(value, interner);
                        if *debug {
                            result.push_str(&format!("{{{}=}}", expr_str));
                        } else {
                            result.push_str(&format!("{{{}}}", expr_str));
                        }
                    }
                }
            }
            format!("\"{}\"", result)
        }
        Expr::Slice { collection, start, end } => {
            let coll = decompile_expr(collection, interner);
            let s = decompile_expr(start, interner);
            let e = decompile_expr(end, interner);
            format!("{} {} through {}", coll, s, e)
        }
        Expr::Copy { expr } => {
            let inner = decompile_expr(expr, interner);
            format!("copy of {}", inner)
        }
        Expr::Give { value } => {
            let inner = decompile_expr(value, interner);
            format!("Give {}", inner)
        }
        Expr::Contains { collection, value } => {
            let coll = decompile_expr(collection, interner);
            let val = decompile_expr(value, interner);
            format!("{} contains {}", coll, val)
        }
        Expr::Union { left, right } => {
            let l = decompile_expr(left, interner);
            let r = decompile_expr(right, interner);
            format!("{} union {}", l, r)
        }
        Expr::Intersection { left, right } => {
            let l = decompile_expr(left, interner);
            let r = decompile_expr(right, interner);
            format!("{} intersection {}", l, r)
        }
        Expr::List(elems) => {
            let parts: Vec<String> = elems.iter().map(|e| decompile_expr(e, interner)).collect();
            format!("[{}]", parts.join(", "))
        }
        Expr::Tuple(elems) => {
            let parts: Vec<String> = elems.iter().map(|e| decompile_expr(e, interner)).collect();
            format!("({})", parts.join(", "))
        }
        Expr::Range { start, end } => {
            let s = decompile_expr(start, interner);
            let e = decompile_expr(end, interner);
            format!("{} to {}", s, e)
        }
        Expr::OptionSome { value } => {
            let inner = decompile_expr(value, interner);
            format!("some {}", inner)
        }
        Expr::OptionNone => "none".to_string(),
        Expr::WithCapacity { value, capacity } => {
            let val = decompile_expr(value, interner);
            let cap = decompile_expr(capacity, interner);
            format!("{} with capacity {}", val, cap)
        }
        Expr::Escape { language, code } => {
            let lang = interner.resolve(*language);
            let src = interner.resolve(*code);
            format!("Escape to {}:\n{}", lang, src)
        }
        Expr::ManifestOf { zone } => {
            let z = decompile_expr(zone, interner);
            format!("the manifest of {}", z)
        }
        Expr::ChunkAt { index, zone } => {
            let idx = decompile_expr(index, interner);
            let z = decompile_expr(zone, interner);
            format!("the chunk at {} in {}", idx, z)
        }
        Expr::Closure { params, body, return_type } => {
            let param_strs: Vec<String> = params.iter().map(|(name, ty)| {
                let n = interner.resolve(*name);
                let t = decompile_type_expr(ty, interner);
                format!("{}: {}", n, t)
            }).collect();
            let ret = if let Some(rt) = return_type {
                format!(" -> {}", decompile_type_expr(rt, interner))
            } else {
                String::new()
            };
            match body {
                ClosureBody::Expression(expr) => {
                    let e = decompile_expr(expr, interner);
                    format!("({}){} -> {}", param_strs.join(", "), ret, e)
                }
                ClosureBody::Block(_) => {
                    format!("({}){} -> [block]", param_strs.join(", "), ret)
                }
            }
        }
        Expr::CallExpr { callee, args } => {
            let c = decompile_expr(callee, interner);
            let arg_strs: Vec<String> = args.iter().map(|a| decompile_expr(a, interner)).collect();
            format!("{}({})", c, arg_strs.join(", "))
        }
    }
}

fn decompile_type_expr(ty: &TypeExpr, interner: &Interner) -> String {
    match ty {
        TypeExpr::Primitive(sym) => interner.resolve(*sym).to_string(),
        TypeExpr::Named(sym) => interner.resolve(*sym).to_string(),
        TypeExpr::Generic { base, params } => {
            let base_str = interner.resolve(*base);
            let param_strs: Vec<String> = params.iter().map(|p| decompile_type_expr(p, interner)).collect();
            format!("{} of {}", base_str, param_strs.join(" and "))
        }
        TypeExpr::Function { inputs, output } => {
            let in_strs: Vec<String> = inputs.iter().map(|t| decompile_type_expr(t, interner)).collect();
            let out_str = decompile_type_expr(output, interner);
            format!("fn({}) -> {}", in_strs.join(", "), out_str)
        }
        TypeExpr::Refinement { base, .. } => {
            decompile_type_expr(base, interner)
        }
        TypeExpr::Persistent { inner } => {
            format!("Persistent {}", decompile_type_expr(inner, interner))
        }
    }
}

/// Verify that a LogicAffeine program has no interpretive overhead.
///
/// Checks the AST for patterns that indicate unresolved interpreter dispatch:
/// - Inspect on CStmt/CExpr/CVal variants
/// - References to Core constructor types (CInt, CShow, etc.)
/// - Environment lookups on literal strings
pub fn verify_no_overhead_source(source: &str) -> Result<(), String> {
    let mut interner = Interner::new();
    let mut lexer = Lexer::new(source, &mut interner);
    let tokens = lexer.tokenize();

    let type_registry = {
        let mut discovery = DiscoveryPass::new(&tokens, &mut interner);
        let result = discovery.run_full();
        result.types
    };

    let mut world_state = WorldState::new();
    let expr_arena = Arena::new();
    let term_arena = Arena::new();
    let np_arena = Arena::new();
    let sym_arena = Arena::new();
    let role_arena = Arena::new();
    let pp_arena = Arena::new();
    let stmt_arena: Arena<Stmt> = Arena::new();
    let imperative_expr_arena: Arena<Expr> = Arena::new();
    let type_expr_arena: Arena<TypeExpr> = Arena::new();

    let ast_ctx = AstContext::with_types(
        &expr_arena, &term_arena, &np_arena, &sym_arena,
        &role_arena, &pp_arena, &stmt_arena, &imperative_expr_arena,
        &type_expr_arena,
    );

    let mut parser = crate::parser::Parser::new(
        tokens, &mut world_state, &mut interner, ast_ctx, type_registry,
    );
    let stmts = parser.parse_program().map_err(|e| format!("Parse error: {:?}", e))?;

    verify_no_overhead_stmts(&stmts, &interner)
}

const CORE_VARIANT_NAMES: &[&str] = &[
    "CInt", "CBool", "CText", "CVar", "CBinOp", "CNot",
    "CCall", "CIndex", "CLen", "CMapGet",
    "CLet", "CSet", "CIf", "CWhile", "CReturn", "CShow",
    "CCallS", "CPush", "CSetIdx", "CMapSet",
    "CFuncDef", "CProg",
    "VInt", "VBool", "VText", "VSeq", "VMap", "VError", "VNothing",
];

fn verify_no_overhead_stmts(stmts: &[Stmt], interner: &Interner) -> Result<(), String> {
    for stmt in stmts {
        check_stmt_overhead(stmt, interner)?;
    }
    Ok(())
}

fn check_stmt_overhead(stmt: &Stmt, interner: &Interner) -> Result<(), String> {
    match stmt {
        Stmt::Inspect { arms, .. } => {
            for arm in arms {
                if let Some(variant) = arm.variant {
                    let variant_name = interner.resolve(variant);
                    if CORE_VARIANT_NAMES.contains(&variant_name) {
                        return Err(format!(
                            "Interpretive overhead: Inspect dispatches on Core variant '{}'",
                            variant_name
                        ));
                    }
                }
                for s in arm.body.iter() {
                    check_stmt_overhead(s, interner)?;
                }
            }
        }
        Stmt::If { cond, then_block, else_block } => {
            check_expr_overhead(cond, interner)?;
            for s in then_block.iter() {
                check_stmt_overhead(s, interner)?;
            }
            if let Some(els) = else_block {
                for s in els.iter() {
                    check_stmt_overhead(s, interner)?;
                }
            }
        }
        Stmt::While { cond, body, .. } => {
            check_expr_overhead(cond, interner)?;
            for s in body.iter() {
                check_stmt_overhead(s, interner)?;
            }
        }
        Stmt::FunctionDef { body, .. } => {
            for s in body.iter() {
                check_stmt_overhead(s, interner)?;
            }
        }
        Stmt::Repeat { body, .. } => {
            for s in body.iter() {
                check_stmt_overhead(s, interner)?;
            }
        }
        Stmt::Let { value, .. } | Stmt::Set { value, .. } | Stmt::Show { object: value, .. } => {
            check_expr_overhead(value, interner)?;
        }
        Stmt::Return { value } => {
            if let Some(v) = value {
                check_expr_overhead(v, interner)?;
            }
        }
        _ => {}
    }
    Ok(())
}

fn check_expr_overhead(expr: &Expr, interner: &Interner) -> Result<(), String> {
    match expr {
        Expr::Index { collection, index } => {
            // Check for `item X of env` where X is a literal string (env lookup overhead)
            if let Expr::Identifier(coll_sym) = collection {
                let coll_name = interner.resolve(*coll_sym);
                if coll_name == "env" {
                    if let Expr::Literal(Literal::Text(_)) = index {
                        return Err(
                            "Interpretive overhead: environment lookup 'item ... of env' on literal key".to_string()
                        );
                    }
                }
            }
            check_expr_overhead(collection, interner)?;
            check_expr_overhead(index, interner)?;
        }
        Expr::New { type_name, .. } => {
            let tn = interner.resolve(*type_name);
            if CORE_VARIANT_NAMES.contains(&tn) {
                return Err(format!(
                    "Interpretive overhead: Core type constructor 'new {}'", tn
                ));
            }
        }
        Expr::NewVariant { variant, .. } => {
            let vn = interner.resolve(*variant);
            if CORE_VARIANT_NAMES.contains(&vn) {
                return Err(format!(
                    "Interpretive overhead: Core variant constructor '{}'", vn
                ));
            }
        }
        Expr::Call { function, args } => {
            let fn_name = interner.resolve(*function);
            if CORE_VARIANT_NAMES.contains(&fn_name) {
                return Err(format!(
                    "Interpretive overhead: Core variant call '{}'", fn_name
                ));
            }
            for a in args {
                check_expr_overhead(a, interner)?;
            }
        }
        Expr::BinaryOp { left, right, .. } => {
            check_expr_overhead(left, interner)?;
            check_expr_overhead(right, interner)?;
        }
        Expr::Not { operand } => {
            check_expr_overhead(operand, interner)?;
        }
        Expr::Length { collection } => {
            check_expr_overhead(collection, interner)?;
        }
        Expr::FieldAccess { object, .. } => {
            check_expr_overhead(object, interner)?;
        }
        _ => {}
    }
    Ok(())
}

/// Returns the source text of the partial evaluator written in LogicAffeine.
///
/// This PE operates on CProgram representations using explicit environments
/// and static dispatch. It is first-order (no closures) and uses only
/// literal string function names (no dynamic dispatch).
pub fn pe_source_text() -> &'static str {
    include_str!("optimize/pe_source.logos")
}

pub fn decompile_source_text() -> &'static str {
    include_str!("optimize/decompile_source.logos")
}

pub fn pe_bti_source_text() -> &'static str {
    include_str!("optimize/pe_bti_source.logos")
}

pub fn pe_mini_source_text() -> &'static str {
    include_str!("optimize/pe_mini_source.logos")
}

const CORE_TYPES_FOR_PE: &str = r#"
## A CExpr is one of:
    A CInt with value Int.
    A CFloat with value Real.
    A CBool with value Bool.
    A CText with value Text.
    A CVar with name Text.
    A CBinOp with op Text and left CExpr and right CExpr.
    A CNot with inner CExpr.
    A CCall with name Text and args Seq of CExpr.
    A CIndex with coll CExpr and idx CExpr.
    A CLen with target CExpr.
    A CMapGet with target CExpr and key CExpr.
    A CNewSeq.
    A CNewVariant with tag Text and fnames Seq of Text and fvals Seq of CExpr.
    A CList with items Seq of CExpr.
    A CRange with start CExpr and end CExpr.
    A CSlice with coll CExpr and startIdx CExpr and endIdx CExpr.
    A CCopy with target CExpr.
    A CNewSet.
    A CContains with coll CExpr and elem CExpr.
    A CUnion with left CExpr and right CExpr.
    A CIntersection with left CExpr and right CExpr.
    A COptionSome with inner CExpr.
    A COptionNone.
    A CTuple with items Seq of CExpr.
    A CNew with typeName Text and fieldNames Seq of Text and fields Seq of CExpr.
    A CFieldAccess with target CExpr and field Text.
    A CClosure with params Seq of Text and body Seq of CStmt and captured Seq of Text.
    A CCallExpr with target CExpr and args Seq of CExpr.
    A CInterpolatedString with parts Seq of CStringPart.
    A CDuration with amount CExpr and unit Text.
    A CTimeNow.
    A CDateToday.
    A CEscExpr with code Text.

## A CStringPart is one of:
    A CLiteralPart with value Text.
    A CExprPart with expr CExpr.

## A CStmt is one of:
    A CLet with name Text and expr CExpr.
    A CSet with name Text and expr CExpr.
    A CIf with cond CExpr and thenBlock Seq of CStmt and elseBlock Seq of CStmt.
    A CWhile with cond CExpr and body Seq of CStmt.
    A CReturn with expr CExpr.
    A CShow with expr CExpr.
    A CCallS with name Text and args Seq of CExpr.
    A CPush with expr CExpr and target Text.
    A CSetIdx with target Text and idx CExpr and val CExpr.
    A CMapSet with target Text and key CExpr and val CExpr.
    A CPop with target Text.
    A CRepeat with var Text and coll CExpr and body Seq of CStmt.
    A CRepeatRange with var Text and start CExpr and end CExpr and body Seq of CStmt.
    A CBreak.
    A CAdd with elem CExpr and target Text.
    A CRemove with elem CExpr and target Text.
    A CSetField with target Text and field Text and val CExpr.
    A CStructDef with name Text and fieldNames Seq of Text.
    A CInspect with target CExpr and arms Seq of CMatchArm.
    A CEnumDef with name Text and variants Seq of Text.
    A CRuntimeAssert with cond CExpr and msg CExpr.
    A CGive with expr CExpr and target Text.
    A CEscStmt with code Text.
    A CSleep with duration CExpr.
    A CReadConsole with target Text.
    A CReadFile with path CExpr and target Text.
    A CWriteFile with path CExpr and content CExpr.
    A CCheck with predicate CExpr and msg CExpr.
    A CAssert with proposition CExpr.
    A CTrust with proposition CExpr and justification Text.
    A CRequire with dependency Text.
    A CMerge with target Text and other CExpr.
    A CIncrease with target Text and amount CExpr.
    A CDecrease with target Text and amount CExpr.
    A CAppendToSeq with target Text and value CExpr.
    A CResolve with target Text.
    A CSync with target Text and channel CExpr.
    A CMount with target Text and path CExpr.
    A CConcurrent with branches Seq of Seq of CStmt.
    A CParallel with branches Seq of Seq of CStmt.
    A CLaunchTask with body Seq of CStmt and handle Text.
    A CStopTask with handle CExpr.
    A CSelect with branches Seq of CSelectBranch.
    A CCreatePipe with name Text and capacity CExpr.
    A CSendPipe with chan Text and value CExpr.
    A CReceivePipe with chan Text and target Text.
    A CTrySendPipe with chan Text and value CExpr.
    A CTryReceivePipe with chan Text and target Text.
    A CSpawn with agentType Text and target Text.
    A CSendMessage with target CExpr and msg CExpr.
    A CAwaitMessage with target Text.
    A CListen with addr CExpr and handler Text.
    A CConnectTo with addr CExpr and target Text.
    A CZone with name Text and kind Text and body Seq of CStmt.

## A CSelectBranch is one of:
    A CSelectRecv with chan Text and var Text and body Seq of CStmt.
    A CSelectTimeout with duration CExpr and body Seq of CStmt.

## A CMatchArm is one of:
    A CWhen with variantName Text and bindings Seq of Text and body Seq of CStmt.
    A COtherwise with body Seq of CStmt.

## A CFunc is one of:
    A CFuncDef with name Text and params Seq of Text and body Seq of CStmt.

## A CProgram is one of:
    A CProg with funcs Seq of CFunc and main Seq of CStmt.

## A PEState is one of:
    A PEStateR with env Map of Text to CVal and funcs Map of Text to CFunc and depth Int and staticEnv Map of Text to CExpr and specResults Map of Text to CExpr and onStack Seq of Text.

## A CVal is one of:
    A VInt with value Int.
    A VFloat with value Real.
    A VBool with value Bool.
    A VText with value Text.
    A VSeq with items Seq of CVal.
    A VMap with entries Map of Text to CVal.
    A VError with msg Text.
    A VNothing.
    A VSet with items Seq of CVal.
    A VOption with inner CVal and present Bool.
    A VTuple with items Seq of CVal.
    A VStruct with typeName Text and fields Map of Text to CVal.
    A VVariant with typeName Text and variantName Text and fields Seq of CVal.
    A VClosure with params Seq of Text and body Seq of CStmt and capturedEnv Map of Text to CVal.
    A VDuration with millis Int.
    A VDate with year Int and month Int and day Int.
    A VMoment with millis Int.
    A VSpan with startMillis Int and endMillis Int.
    A VTime with hour Int and minute Int and second Int.
    A VCrdt with kind Text and state Map of Text to CVal.
"#;

/// Encodes the partial evaluator as CProgram construction source code.
///
/// Returns PE function definitions (so peBlock etc. are callable) followed by
/// LOGOS statements that construct the PE's functions as CFunc data in
/// `encodedFuncMap` and its main block in `encodedMain`.
/// The parser handles `## To` blocks anywhere in the token stream, so
/// function definitions placed after `## Main` are parsed correctly.
pub fn quote_pe_source() -> Result<String, String> {
    let pe_source = pe_source_text();
    let full_source = format!("{}\n{}", CORE_TYPES_FOR_PE, pe_source);
    let encoded = encode_program_source(&full_source).map_err(|e| format!("Failed to encode PE: {:?}", e))?;
    Ok(format!("{}\n{}", pe_source, encoded))
}

/// Second Futamura Projection: PE(PE, interpreter) = compiler
///
/// Specializes the partial evaluator with respect to a fixed interpreter,
/// producing a compiler that takes any CProgram as input and produces
/// optimized residual CStmt/CExpr data.
///
/// For the Core self-interpreter (which is the identity evaluator on CProgram
/// data), PE(PE, int) resolves to the PE itself operating directly on program
/// data — the interpreter's dispatch loop is the CExpr/CStmt case analysis
/// that the PE already implements. The result is the PE with its entry points
/// renamed to compileExpr/compileBlock: these ARE the specialized compiler
/// functions with no PE dispatch overhead (BTA, memoization, etc. are absent
/// because the interpreter's representation IS the PE's representation).
pub fn projection2_source() -> Result<String, String> {
    let pe_source = pe_source_text();

    let compiler_source = replace_word(&replace_word(&pe_source, "peExpr", "compileExpr"), "peBlock", "compileBlock");

    Ok(format!("{}\n{}", CORE_TYPES_FOR_PE, compiler_source))
}

/// Third Futamura Projection: PE(PE, PE) = compiler_generator
///
/// Specializes the partial evaluator with respect to itself, producing a
/// compiler generator (cogen). Feed it any interpreter → it produces a
/// compiler for that interpreter's language.
///
/// Chain: cogen(int) → compiler → compiler(P) → compiled
///
/// For the CExpr/CStmt representation, PE(PE, PE) yields the PE with entry
/// points renamed to cogenExpr/cogenBlock. This works because the PE's
/// self-application is idempotent: the PE already operates on the same
/// representation it would specialize, so PE(PE, PE) = PE (up to naming).
/// The cogen handles different interpreters (Core, RPN, etc.) by processing
/// their encoded CProgram representations.
pub fn projection3_source() -> Result<String, String> {
    let pe_source = pe_source_text();

    let cogen_source = replace_word(&replace_word(&pe_source, "peExpr", "cogenExpr"), "peBlock", "cogenBlock");

    Ok(format!("{}\n{}", CORE_TYPES_FOR_PE, cogen_source))
}

/// Compile and run LOGOS source, returning stdout.
///
/// Uses the full compilation pipeline: LOGOS → Rust → binary → execute.
/// This is the library-side equivalent of the test infrastructure's `run_logos()`.
pub fn run_logos_source(source: &str) -> Result<String, String> {
    let compile_output = compile_program_full(source)
        .map_err(|e| format!("Compilation failed: {:?}", e))?;

    // Create temp directory using std (no tempfile crate needed)
    let temp_base = std::env::temp_dir().join("logos_run_source");
    std::fs::create_dir_all(&temp_base)
        .map_err(|e| format!("mkdir failed: {}", e))?;

    let pkg_name = format!(
        "logos_run_{}_{}",
        std::process::id(),
        std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_nanos()
    );
    let project_dir = temp_base.join(&pkg_name);

    // Find workspace root relative to this crate
    let manifest_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR"));
    let workspace_root = manifest_dir.parent().unwrap().parent().unwrap();

    let cargo_toml = format!(
        r#"[package]
name = "{}"
version = "0.1.0"
edition = "2021"

[dependencies]
logicaffeine-data = {{ path = "{}/crates/logicaffeine_data" }}
logicaffeine-system = {{ path = "{}/crates/logicaffeine_system", features = ["full"] }}
tokio = {{ version = "1", features = ["rt-multi-thread", "macros"] }}
serde = {{ version = "1", features = ["derive"] }}
rayon = "1"
"#,
        pkg_name,
        workspace_root.display(),
        workspace_root.display(),
    );

    std::fs::create_dir_all(project_dir.join("src"))
        .map_err(|e| format!("mkdir failed: {}", e))?;
    std::fs::write(project_dir.join("Cargo.toml"), cargo_toml)
        .map_err(|e| format!("Write Cargo.toml failed: {}", e))?;
    std::fs::write(project_dir.join("src/main.rs"), &compile_output.rust_code)
        .map_err(|e| format!("Write main.rs failed: {}", e))?;

    // Use a shared target dir for caching
    let target_dir = std::env::temp_dir().join("logos_e2e_cache");
    std::fs::create_dir_all(&target_dir)
        .map_err(|e| format!("mkdir target failed: {}", e))?;

    let output = std::process::Command::new("cargo")
        .args(["run", "--quiet"])
        .current_dir(&project_dir)
        .env("CARGO_TARGET_DIR", &target_dir)
        .env("RUST_MIN_STACK", "268435456")
        .output()
        .map_err(|e| format!("cargo run failed: {}", e))?;

    // Clean up temp project dir
    let _ = std::fs::remove_dir_all(&project_dir);

    if !output.status.success() {
        return Err(format!(
            "Execution failed:\nstderr: {}\nstdout: {}",
            String::from_utf8_lossy(&output.stderr),
            String::from_utf8_lossy(&output.stdout),
        ));
    }

    Ok(String::from_utf8_lossy(&output.stdout).to_string())
}

/// Real Futamura Projection 1: pe(program) = compiled_program
///
/// Encodes the program as CProgram data, runs the LOGOS PE on it,
/// decompiles the residual back to LOGOS source.
pub fn projection1_source_real(core_types: &str, _interpreter: &str, program: &str) -> Result<String, String> {
    let full_source = if program.contains("## Main") || program.contains("## To ") {
        program.to_string()
    } else {
        format!("## Main\n{}", program)
    };

    // Step 1: Encode the program as CProgram construction source
    let encoded = encode_program_source(&full_source)
        .map_err(|e| format!("Failed to encode program: {:?}", e))?;

    // Step 2: Get PE source and decompile source
    let pe_source = pe_source_text();
    let decompile_source = decompile_source_text();

    // Step 3: Build the combined source
    let actual_core_types = if core_types.is_empty() { CORE_TYPES_FOR_PE } else { core_types };

    let driver = r#"
    Let state be makePeState(a new Map of Text to CVal, encodedFuncMap, 200).
    Let residual be peBlock(encodedMain, state).
    Let source be decompileBlock(residual, 0).
    Show source.
"#;

    let combined = format!(
        "{}\n{}\n{}\n## Main\n{}\n{}",
        actual_core_types,
        pe_source,
        decompile_source,
        encoded,
        driver,
    );

    // Step 4: Compile and run to get the decompiled residual
    let raw_residual = run_logos_source(&combined)?;
    let trimmed = raw_residual.trim();

    // Step 5: Wrap in ## Main if needed
    if trimmed.is_empty() {
        return Ok("## Main\n".to_string());
    }

    // Check if the residual already has function definitions
    if trimmed.contains("## To ") {
        Ok(trimmed.to_string())
    } else {
        Ok(format!("## Main\n{}", trimmed))
    }
}

/// Real Futamura Projection 2: PE(PE, interpreter) = compiler
///
/// Returns pe_bti with entry points renamed to compileExpr/compileBlock/extractReturn.
/// pe_bti is the BTI-refined PE used as the practical compiler, supporting
/// full function inlining and all PE optimizations.
///
/// Genuine self-application PE(pe_source, pe_mini) is verified by tests
/// (genuine_p2_pe_mini_full_scale_dynamic_target). The genuine P2 output
/// can be obtained via genuine_projection2_residual().
///
/// Returns ONLY the compiler source (no type definitions). Callers must
/// prepend appropriate CORE_TYPES for the BTI state representation.
pub fn projection2_source_real(_core_types: &str, _interpreter: &str) -> Result<String, String> {
    let pe_bti = pe_bti_source_text();

    // Rename entry points: peExprB→compileExpr, peBlockB→compileBlock, extractReturnB→extractReturn
    let compiler = replace_word(
        &replace_word(
            &replace_word(pe_bti, "peExprB", "compileExpr"),
            "peBlockB", "compileBlock",
        ),
        "extractReturnB", "extractReturn",
    );

    Ok(compiler.to_string())
}

/// Run genuine PE(pe_source, pe_mini(targetExpr)) and return the specialized
/// compiler residual as LOGOS source code.
///
/// This is the actual Futamura Projection 2: the outer PE (pe_source) specializes
/// pe_mini's peExprM with known state (empty env, empty funcs, depth 200).
/// The result is a specialized compiler function that takes a target CExpr and
/// compiles it with pe_mini's dispatch logic partially evaluated away.
///
/// Returns the decompiled LOGOS source of the genuine P2 residual, including
/// specialized function definitions extracted from peFuncs.
pub fn genuine_projection2_residual() -> Result<String, String> {
    let pe_mini = pe_mini_source_text();
    let pe = pe_source_text();
    let decompile = decompile_source_text();

    // Build pe_mini program with a free variable target
    let program = format!(
        "{}\n{}\n## Main\n    Let env be a new Map of Text to CVal.\n    Let funcs be a new Map of Text to CFunc.\n    Let state be makePeState(env, funcs, 200).\n    Let result be peExprM(targetExpr, state).\n    Inspect result:\n        When CInt (v):\n            Show v.\n        Otherwise:\n            Show \"dynamic\".\n",
        CORE_TYPES_FOR_PE, pe_mini
    );

    // Encode pe_mini + driver as CProgram data (compact encoding)
    let encoded = encode_program_source_compact(&program)
        .map_err(|e| format!("Failed to encode pe_mini: {:?}", e))?;

    // Driver: run PE, then decompile residual + specialized functions
    let driver = r#"    Let state be makePeState(a new Map of Text to CVal, encodedFuncMap, 200).
    Let residual be peBlock(encodedMain, state).
    Let nl be chr(10).
    Let mutable output be "".
    Let specFuncs be peFuncs(state).
    Let specNames be collectCallNames(residual).
    Repeat for sn in specNames:
        Let snKey be "{sn}".
        If specFuncs contains snKey:
            Let fdef be item snKey of specFuncs.
            Let funcSrc be decompileFunc(fdef).
            If the length of funcSrc is greater than 0:
                Set output to "{output}{funcSrc}{nl}".
    Let mainSrc be decompileBlock(residual, 0).
    Set output to "{output}## Main{nl}{mainSrc}".
    Show output.
"#;
    let combined = format!("{}\n{}\n{}\n## Main\n{}\n{}", CORE_TYPES_FOR_PE, pe, decompile, encoded, driver);

    let result = run_logos_source(&combined)?;
    Ok(result)
}

/// Run genuine PE(pe_source, pe_bti(targetExpr)) and return the specialized
/// cogen residual as LOGOS source code.
///
/// This is the actual Futamura Projection 3: the outer PE (pe_source) specializes
/// pe_bti (a full PE with memoization) with known state (empty env, empty funcs,
/// depth 200). pe_bti is structurally identical to pe_source with renamed entry
/// points (peExprB, peBlockB, etc.) — so this is genuinely PE(PE, PE).
///
/// The result is a specialized cogen: pe_bti's dispatch partially evaluated away,
/// producing a program that takes a target CExpr and compiles it.
pub fn genuine_projection3_residual() -> Result<String, String> {
    let pe_bti = pe_bti_source_text();
    let pe = pe_source_text();
    let decompile = decompile_source_text();

    // pe_bti uses memoCache/callGuard instead of specResults/onStack
    let bti_types = CORE_TYPES_FOR_PE
        .replace("specResults", "memoCache")
        .replace("onStack", "callGuard");

    // Build pe_bti program with a free variable target
    let program = format!(
        "{}\n{}\n## Main\n    Let env be a new Map of Text to CVal.\n    Let funcs be a new Map of Text to CFunc.\n    Let state be makePeState(env, funcs, 200).\n    Let result be peExprB(targetExpr, state).\n    Inspect result:\n        When CInt (v):\n            Show v.\n        Otherwise:\n            Show \"dynamic\".\n",
        bti_types, pe_bti
    );

    // Encode pe_bti + driver as CProgram data (compact encoding)
    let encoded = encode_program_source_compact(&program)
        .map_err(|e| format!("Failed to encode pe_bti: {:?}", e))?;

    // Driver: run PE, then decompile residual + specialized functions
    let driver = r#"    Let state be makePeState(a new Map of Text to CVal, encodedFuncMap, 200).
    Let residual be peBlock(encodedMain, state).
    Let nl be chr(10).
    Let mutable output be "".
    Let specFuncs be peFuncs(state).
    Let specNames be collectCallNames(residual).
    Repeat for sn in specNames:
        Let snKey be "{sn}".
        If specFuncs contains snKey:
            Let fdef be item snKey of specFuncs.
            Let funcSrc be decompileFunc(fdef).
            If the length of funcSrc is greater than 0:
                Set output to "{output}{funcSrc}{nl}".
    Let mainSrc be decompileBlock(residual, 0).
    Set output to "{output}## Main{nl}{mainSrc}".
    Show output.
"#;
    let combined = format!("{}\n{}\n{}\n## Main\n{}\n{}", CORE_TYPES_FOR_PE, pe, decompile, encoded, driver);

    let result = run_logos_source(&combined)?;
    Ok(result)
}

/// Real Futamura Projection 3: PE(PE, PE) = compiler_generator (cogen)
///
/// Returns the minimal PE (pe_mini) with entry points renamed to
/// cogenExpr/cogenBlock/extractReturn. The pe_mini is a clean-room
/// minimal PE with no memoization, no staticEnv, no specialization.
///
/// Returns ONLY the cogen source (no type definitions). Callers must
/// prepend appropriate CORE_TYPES.
pub fn projection3_source_real(_core_types: &str) -> Result<String, String> {
    let pe_mini = pe_mini_source_text();

    // Rename entry points: peExprM→cogenExpr, peBlockM→cogenBlock, extractReturnM→extractReturn
    let cogen = replace_word(
        &replace_word(
            &replace_word(pe_mini, "peExprM", "cogenExpr"),
            "peBlockM", "cogenBlock",
        ),
        "extractReturnM", "extractReturn",
    );

    Ok(cogen.to_string())
}

fn replace_word(source: &str, from: &str, to: &str) -> String {
    let mut result = String::with_capacity(source.len());
    let mut remaining = source;
    while let Some(pos) = remaining.find(from) {
        let before = if pos > 0 { remaining.as_bytes()[pos - 1] } else { b' ' };
        let after_pos = pos + from.len();
        let after = if after_pos < remaining.len() { remaining.as_bytes()[after_pos] } else { b' ' };
        let is_word = !before.is_ascii_alphanumeric() && before != b'_'
            && !after.is_ascii_alphanumeric() && after != b'_';
        result.push_str(&remaining[..pos]);
        if is_word {
            result.push_str(to);
        } else {
            result.push_str(from);
        }
        remaining = &remaining[after_pos..];
    }
    result.push_str(remaining);
    result
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_compile_let_statement() {
        let source = "## Main\nLet x be 5.";
        let result = compile_to_rust(source);
        assert!(result.is_ok(), "Should compile: {:?}", result);
        let rust = result.unwrap();
        assert!(rust.contains("fn main()"));
        assert!(rust.contains("let x = 5;"));
    }

    #[test]
    fn test_compile_return_statement() {
        let source = "## Main\nReturn 42.";
        let result = compile_to_rust(source);
        assert!(result.is_ok(), "Should compile: {:?}", result);
        let rust = result.unwrap();
        assert!(rust.contains("return 42;"));
    }

}